Our Bike Electric

From acorns mighty, um, bikes. I'd seemed to have accumulated three bikes since coming back to Sheffield - each a bargain that couldn't be passed by. Anyways, I'd had a spin on a friend's, and borrowed one from Halfords for a day. So I was impressed, and the promise of (cursed) work from October 22 meant some unplanned cash. Then so off to ebay with me to hatch a plan to convert one of the bikes . . .
Donor Bike
This is a well used 20 year old mid-range mountain bike. I'd recently replaced the rear wheel, bottom bracket and tyres, and it's just sat there as I use an (even) older and less flash bike for pottering. I figured that it should be reasonably strong, could sate some misplaced notion that I could cycle over crags, and it has decent hydraulic disc brakes that could handle the extra weight.
The Conversion
Choices choices. Rear wheel, front wheel, mid-drive. Cost, value, range, weight. Then there's legality, provenance of the parts, safety for myself and others. A project ripe for overthought. By all means get in touch if you'd like to talk it through. In the end I sided with a mid-drive, proven, sort of legal second hand set of parts. It cost me £370. Not trivial, certainly, And on to the bits and bolting it all together . . .
The Parts
Preparation and Assembly