This year I would like a Jersey cow with a heifer at foot and a bull calf fostered on, Does anyone know a breeder or farm up north who might be willing to provide somthing like this?
In a word, no. Most of the Jerseys about are dairy cows, so do not rear their own calves let alone another.
Having said which, many farms have a Jersey or two to rear orphaned calves. Mostly they probably don't put her to a Jersey though, so if you were wanting a Jersey heifer calf at foot that would be hard to find. And she would be an older cow.
You can buy in-calf Jerseys from some dairy herds, so I guess you could enquire whether any would take an order for one with a new-born calf; and perhaps they would be prepared to set a foster calf on her for you. I think you would be looking at a lot of money though - maybe £3000 or even more.
The only other approach I could see working would be finding a 'nursemaid' (older) Jersey who has been used to suckle multiple calves but isn't suitable for use in the parlour. Again you could maybe commission the farm to produce her as the outfit you describe.
I'd be interested to know how you get on.