We’ve sold e-MTBs for a good few years now. Haibike were our first brand and they’re decent quality. Specs have come down over the last couple of years to maintain pricing but still not bad. KTM is also worth a look, and Mondraker too.
Bosch system is the market leader and better than Yamaha, but Yamaha is cheaper and at £2k you might get more in terms of the rest of the spec if you did go Yamaha. I’d probably still recommend a Bosch system though as it’s the only part you’re not going to be able to upgrade later.
A new brand for us this year, and the one we’re using for our hire bikes, is Moustache. They’re a small French company and the bikes are built in the Voges with frames manufactured to their spec in the far east. Quality is head and shoulders above anything else I’ve seen. Really pleased. Start at just a smidge over £2k, but possibly worth considering.
http://www.moustachebikes.com/uk/
If you’d like a run-down on the range, give us a shout!