I have an old Airtronics CS2P radio, are the receiver s still availble to buy, if so any ideas where I can get one?

Yes you can still get receivers. That's same radio I've been using for a long time but I just updated to an M8 with Spektrum conversion. Any of the newer blue Airtronics receivers will work. Really any matching receiver will work also, it doesn't have to be Airtronics.

Something like this will work
http://www.airtronics.net/index.php/...se-4731xx.html

I'm just guessing your radio is 75 Mhz though, it could be 27 Mhz. Check your module on the top of the transmitter.