The pile of congealed lamb fat in front of me started to become an annoyance — when would the plate be cleared? — just before that musical irritant Acker Bilk struck up over the sound system with his depressing Stranger on the Shore. It was still annoying me 20 minutes later, by which time Acker had gone on to assail our ears with his own vexing takes on Don’t Cry For Me Argentina, Bridge Over Troubled Water and Nature Boy. He was midway through Amazing Grace when — appropriately in view of the title — a waiter at last arrived to perform his duty.

What had all the staff been doing? A strange disappearing act, it seemed. With the exacting maitre d’ Giuseppe Vurchio clearly on a night off, the Randolph’s remaining ‘front-of-house’ team on Monday last were occupying themselves with behind-the-scenes business that had no obvious relevance to the needs of their customers.

After our main courses were served, Rosemarie could find no one on hand to ask for the mustard she wanted with her braised shin of beef. She was obliged to start waving her arms around like a schoolboy seeking teacher’s permission to visit the loo. Once her request had been made, there was a long wait for delivery of the condiment and of the redcurrant jelly I needed with my lamb. Apologies, to be fair, were forthcoming.

During the long interlude in which the plates awaited collection, I seriously considered giving the restaurant a call. The idea was suggested by a picture on the wall behind me in which a Byronesque youth posed, head relaxing languidly on hand, just as if he was talking into his mobile.

The deficiencies in service seriously marred our enjoyment of a meal that we had hoped might be a rather special event. Recent reports in the national press suggested the Randolph was on something of a high at present — which in culinary terms under chef Tom Birks it clearly is. But, of course, there is much more to a happy dinner than good food. Pleasing ambience — which does not permit of Bilk and his clarinet — and cheery, motivated staff matter greatly to me.

Monday’s first calling off point was the Morse Bar — so named, of course, for the fictional TV detective in whose investigations, as in those of his successor Lewis, the hotel has frequently figured.

It is a curious circumstance, perhaps, that the grumpy sleuth should be commemorated in a bar which offers not one example of the real ales which he so famously enjoyed.

Rosemarie likes them, too, but settled on this occasion for a glass of sauvignon blanc (the wine list said Chilean, the bottle said French). On this very warm night, the wine was far from being at its proper temperature — the barmaid explained there had been a refrigerator malfunction of some sort — and ice cubes were called for. They melted almost immediately after immersion, as did the one placed in my Tio Pepe sherry.

If the cost of these drinks (see right) seems excessive, it should be pointed out they came with a generous dish of salted almonds, green and black olives, and biscuity nibbles shaped like tiny baguettes.

In between taking sneaky glances at an elderly couple next to us — was it piquet they were playing? — we studied the menus and placed our orders. With the carte rather on the pricey side (£30-plus a head for two courses) and, moreover, fairly limited, we both opted for the table d’hôte menu, which offered better value and variety.

Soon we were taken through into the restaurant and seated at a small table at the north end of it. This offered a fine view, for me, of the Martyrs’ Memorial and, for Rosemarie, of the Ashmolean, and, for both of us, of the rich decoration that characterises this well-proportioned room.

Both our starters were splendid. Mine was a delicious cold timbale of halibut, prawns and (unadvertised) salmon topped with a rich cream cheese. Rosemarie had potted crab, served in a fish-paste-type lidded glass jar with lemon and chive crème fraîche.

There was a good selection of breads offered, including one with sun-dried tomatoes and another (which I had) with olives. Rosemarie noted that one side of her slice was dry. This suggested it had been cut from a previously broached loaf and ought to have been discarded.

For my main course (after glasses of a complimentary, and unexpected, green apple sorbet) I selected roast leg of lamb ‘from the trolley’. The description suggested to me that this impressive conveyance was going to be pushed into position beside the table — they usually are — allowing me to point out my requirements to the carver. Instead, the meat was delivered already sliced, together with vegetables — roast potatoes, cauliflower, broccoli and green beans — and a red-pepper based ‘chutney’.

The ‘plated-up’ approach was what might be expected in a simple country pub or a works canteen, not in the restaurant of an up-market hotel. That said, the food was uniformly excellent, with the meat exceptionally sweet and tender.

Rosemarie’s shin of beef was likewise most impressive, the meat picked from the bone and rolled, and presented with creamed potatoes and carrot purée (not much of it) on a bed of spinach with onion.

We drank a robust North American merlot which, though it went well with the meat, was rather too — yes, you’ve got it — warm. It was reminiscent of wine served in a country kitchen by a member of the green welly brigade who sincerely believes a red is best left resting on top of the Aga. It really isn’t.

A shared dark and white chocolate ‘truffle’ (a sort of round layered cake of wickedly indulgent content) completed the meal, rendering all but unnecessary the petit fours that came with my decaffeinated coffee.

At this point, ostensibly for ‘a friend’ but really for me in the preparation of this article, Rosemarie asked for a copy of the menu. In fact she asked twice and was twice told it would be supplied. It was not — either deliberately denied her or else forgotten as the staff busied themselves about transforming the restaurant in preparation for Tuesday’s breakfast.

This ought properly to have waited, of course, until the last punters had left. But that was to hope too much: customers here seem to be nothing more than an irritating impediment to the inexorable progress of hotel routine.