CAPCur error message

Hello
I have a 2008 Vectrix which, I'd recently been thinking, has been going very well.... (18,000 miles on the clock) until the CAPCur error message came up and stayed. The advice I've had is that it will require the motor controller to be replaced, at a cost of £2200. Before going ahead, I'm keen to check out if there may be any other options e.g. if there may be a source of second-hand parts in the UK that may be cheaper, or any other thoughts anyone out there may have.
Thanks