@rpbook
in that price range you'll get what you pay for... and it won't be great.
Avoid anything from halfords, their own bikes (carrera) are absolute garbage with controllers that fail after a few hundred miles.... I know, because I had 2 of them, first failed after 350 miles, they replaced it and 2nd one failed after 360 miles... then they tried to pull a load of bullshit to try and deny my consumer rights and I had to resort to a section 75 on the credit card to get my money back.
If you can afford a better budget, go for something with the Bosch mid drive system. The motor is in the pedal assembly and far superior to the hub motors fitted to wheels in the cheap (crappy) ones. Yamaha do a similar system, but I can only speak for the (fantastic) bosch one I have now.
I used to be the sort of person who would buy what was cheaper, I got burned far to many times... so now I buy the best I can afford without going for crazy expensive.
I ended up with a Haibike Trekking hybrid city bike for £1999 back in late 2023, aside from tweaking the chain and adjusting the gearing. It's been flawless, and the exact same framed bike from lapierre (both owned by Raleigh) had the lower power motor and smaller battery than the haibike, whilst costing £400 more. Mine was on sale reduced from £2699.
I can get 50-60 miles out of one charge, depending on hills. I've just done 30 miles in 2 trips this last week and have 52% battery left.
With a £600 budget, you'll either get a knackered bike, a cheap piece of crap (in my opinion) and probably some badly built cheap chinese knock off with a sketchy battery... and the probability of a lot of buyers remorse a little while down the road (just like I had buying from halfrauds).
I hope you get something good
I and others also post stuff (often pics) under the #EbikeRides tag too.