Serious (genuine question): why didn't the captain stay in Manchester circuit and get it down there again as soon as he could ? (they've got twin runways, after all, surely a 'Mayday' has priority). Why go wandering off ? (Obviously there's a good technical answer, but what is it ?)
Serious answer; Fuel.
When he punches off to Costa del Whatever he is carrying a lot of fuel. Because of the tight schedules probably enough for both ways. As a result he is way above his landing weight. He could land in an emergency but as you know you can go for some time on one engine. He can either burn off the fuel which takes ages and is not popular with worried passengers or he can jettison it. The inhabitants of Manchester are not happy if you dump a load of Jet A over their washing lines so they have to climb above 3,000 ft. to ensure the fuel vapour does not descend to ground level.
It is tactful to wander off to a quiet corner of the country so that the onlookers on the ground do not phone the local rag reporting an airliner enveloped in flames and trailing clouds of smoke. Above cloud is ideal.
It happens quite often. Not the engine failure bit but other reasons.
When I was on the mighty Valiant years ago the SOP was to jettison the dregs left in the underwing tanks just before you started your final descent. Another SOP was that on arrival at the circuit the pilots would use any fuel in excess of 10,000 lbs bashing the circuit, ILS etc. On a Friday afternoon skilful and experienced pilots like myself would hoard enormous amounts of fuel in the underwings which were required to be jettisoned at the top of the descent. Invariably this resulted in the fuel contents being approximately 10,000 lbs on finals.
Never missed the shutters going up at TGIF.