After seeing that cute red scoot at £1250, I thought about converting my really low use mountain bike.
Then thought "Nope"!
You can buy a kit that is complete, except for the battery, for considerably less money. I got a 1000w, 48V wheel kit recently for about $200. The battery set me back another $140. I am hoping to cobble this kit onto an old cantilever framed cruiser, but there will definitely be some file work, some spreading of steel stays, and perhaps even a bit of welding involved.
Dropout and fork width and axle diameters of 50 years ago didn't anticipate E-bike developments. Modern mountain bikes are quite a bit easier, since the latest ones are generally designed to accommodate disc brakes and wide range derailleur hubs. I have read that all that may be required is some boring out and filing of the fork or rear dropouts, and the rest is bolt-on.
Privately owned E-bicycles are starting to show up on northwest side Chicago streets this summer as relatively common sights. Probably much more common in the downtown areas, I seldom visit, where parking is largely in high rise structures or underground and extremely expensive, on the order of $8/hr or $25/day. Avoiding that expense alone would pay for a nice bicycle pretty quickly, not even considering gas, insurance, registration and the rest.
Divy bike, our preferred local bicycle rental source, with a city contract and electronic bike vending stations for human and electric powered bikes in every neighborhood, started operating E-bicycles at least a year ago, and those are a very common sight indeed. These are step through framed, heavy duty, very homely things.