Dave, just looked at the eiger with the Nuvinci option this ticks a lot of the boxes can I do without a throttle?You confused me whether you like the idea of a MTB bike or a roady bike....You may wish to look at our new Kudos Sprint,the semi integral battery installation is very neat,the 24" wheels and long seat post allows this bike to be ridden by someone less than 5ft,it has good hill climbing power,price £895.00
If you want a more conventional step thru the Kudos Verona and Milano are good value at £795.00,your height is ok.
I would avoid any crank drive which has torque sensor and any torque sensor e-bike,you need to put power in to get power out,your health may not allow you to do that.
It is not necessary to spend your budget of £1500.00
Good luck with your search.
KudosDave
Can you contrive a 2015 frame to accommodate throttle?
How does the TCM Crank drive stack up against Bafang?