Any decent sellers around? I hear a mid drive is better on hills than a rear hub motor so will probably go with that style.

Not Patts, but if around Bangkok, then BkkEbike:

https://www.bkkebike.com/e-bike-thailand

 

I converted my Schwinn to an ebike, 1000w / 48v30Ah, and was easy enough to do.

Not exactly inexpensive to do; Bike (had) 11k, motor 7250, battery 2890.  Battery is iffy, suspect specs are off a bit, or mismatched with 1000w motor instead of 250 or 350w motor.  Only get about 15 kms, all motor, no pedaling, before hitting about 30% reserve on battery.  15 kms plenty for my use though, and gets me to the surf and back home, with plenty to spare.