Hi Dave,
The new one (Left one in the photo) looks like its from an XM MK2 which both buttons (Lock/unlock and Alarm/deadlock) activate a 'RF' transmitter signal, rather than your original Xantia set up which will be an 'IR' beam to the roof receiver (Lock/Unlock) and then the second button will be a 'RF' transmitter (Alarm/deadlock) !
I hope that makes sense to you, and BTW what did the seller advertise/list it as suitable for ? If its been listed wrong return it and get a refund !
Many times I've seen E-Bay listings stating that 'This plip is suitable for Xantia and XM's' and it plainly obvious that some idiots have not got a clue as to what there listing and suitability as most of the photos I seen with this error usually has the Infra-Red bulb head poking out of the case at the front (Which are only suitable for Xantias)
You seem to have got one from an XM MK2 (If it is you'd need the matching Textron Receiver box to make work but it will be of no use for your Xantia) !
If you need a IR/RF transmitter/plip as the one on the right in the photo (and matching roof receiver) or was it just a decent case you were after ?
PM me and hopefully I may be able to help you out
