Go with Halfords for they will fix it for you if something will go wrong. Of course their bikes are not bargain, the parts are cheap for the price, and build quality is merely acceptable. If it was for something more serious like daily commuting I would get a decent mid-range hybrid bike, convert it and learn how to maintain it and fix it yourself.
I mentioned the Carrera Subway electric above.
Very nice 6061 frame. Their frames used to be made by Merida, although I'm not sure who does them now. Either way, a proper spec material and welded very cleanly.
4130 CroMo fork. Very respectable grade of material, in the past often used in aircraft structures and still favoured by many for touring bike frames. It has very similar mechanical properties to Reynolds 531, so is a long, long way from being mere gas pipe.
Shimano drivetrain with plated KMC chain. OK, only Altus, but it works cleanly and efficiently, as only Shimano seem to know how to do with budget geartrains.
Full Suntour HESC system, from display to motor and everything in between. No cheap unbranded Chinese bits snuck in.
Very effective Tektro hydraulic brakes.
Even the Kenda reflex belted tyres are decent.
So I would be very interested to know which components are "cheap for the price ", because to my mind it's an extremely effective, well thought out specification?
There are some models in the range that feature a less than desirable mix of components - the vengeance ebike, for example - but you're assertion that Carrera bikes are somehow a bit cheap and nasty is far, far from universally true. In fact there are some genuine gems in their range, if you actually know what you're looking at.
The OP came to us for sensible advice, not misinformation or brand prejudice.
PS - no, I don't work for Halfords, and don't own a Carrera ebike (my ebikes are Trek and Felt). However, I have spent a few weeks with my SiLs Subway electric while he was on holiday and it is a very respectable machine in it's own right, and for the money a real gem.