Thanks for the input chaps. I thought I would post an update. I have investigated further. Second hand fobs on eBay sell for around £25, I am fortunate that I have a Jeep breakers near me but they want £25 plus Vat also.
I would then need to get them reprogrammed, my main dealer ha quoted me £23 plus Vat. The main dealer (Marshalls Cambridge) will however supply and programme two NEW fobs for £125 inclusive. For once, the main dealer is the most attractive.