Ouch Jayne! Sorry to hear about your prang, but very glad you survived to tell the tale. Hope you don't have to spend too much time hobbling about!
Can't help with parts supplier recommendations I'm afraid, but someone here may have a better idea of where to get the brake lever at a sensible price.
**Edit** There is this -
https://www.ebay.co.uk/itm/235895667...mis&media=COPY