Here's what happened!
I rang Travel Republic in my lunch hour, spoke to somebody who didn't sound too clued up, kept putting me on hold, only to come back and tell me the charge to cancel flight would be just £30. That's ok I thought?
So I asked would it be possible to use the remaining money towards something else, hold again-for ages. At this point I had to hang up as my lunch hour had run out.
I rang them again in the evening to be told the charge would be £75, I asked them to check this as I had been advised £30 previously?
Definately £75.
The upshot being, I have used the remainder towards a week in Fuerteventura next Feb, in a bungalow by the sea, result, well sort of.
Hope this will teach me not to be so impulsive!
I think not....