Thank you Danidl for the thought about the relative position of the crank. That's definitely something I'll bear in mind as I test. I do have a bike rack (fits over the hatchback) but I think weight is an issue - both for getting the bike on to the rack and just getting it in and out of the the place it will be kept (a narrow space where it has to be got over a door cill). And I should have said that the budget is not unlimited! £1500 is the absolute maximum.
Thank you, too, for the info about the cables, Old grumpy.