Just thought I'd update on this, I had the choice of buying a new key which would have cost around £50.00 and taken approximately 4 weeks to come through or a new sender/receiver kit which could be obtained in 2 days costing £165.82, I chose the latter and fitting was a ten minute job, all working fine, weirdly the senders don't come with the wee screws to hold the two parts together so if your keys are stolen like mine, you have to find something to do the job.
Moral to this saga is, don't leave your keys down when you have workmen in, the set that got lifted carried my Peugeot key, house keys and the only key for an old Granada Scorpio I'm restoring, and I don't have a key number, probably end up scrapping it now :0(
Rab