Financially almost certainly not worthwhile. 5 years ago I planted a black variety (£13), erected 5 cheap arches (£25) second hand wine press (£30) a refractometer to monitor the sugar content (£16) an old oak barrel (£20) a book (£6) wine filter (£15) a sturdy plastic 'half barrel' for treading the grapes (£13) netting (£6) wine racks (£7) secondhand colour laser printer for labels (£7) a sodastream to carbonate the wine (£18) champagne bottle stoppers, cages and foil, various fresh chemicals and a new siphon. Last year the vine produced enough to make 2 bottles of unexceptional fizz. This year, at a pinch, I may get 4.
Having bought, planted, supported, trained, fed, watered, pruned and protected the vine, the whole crop can be destroyed by late frost, mildew and other diseases and in more northerly latitudes you need a really good summer to have any chance of fully ripening.
Personally, I love it and now have 5 vines, but if I had just acquired an allotment which is possibly somewhat unkempt, I would plant potatoes!