This might seem like an odd question, but bare with me....

We have entered a team in a 6hr endurance buggy race where we all share the same car. Problem is that whilst 3 members of the team use a Spekky wheel Tx, one driver uses Spekky sticks.

My question is, can we bind both Tx's to a single SR300 or SR3000 Rx, so when we have a driver change, we just switch off one Tx and turn on the other, or would we need to re-bind each time?

You will have to rebind each time. Receivers are bound to transmitters, not transmitters bound to receivers.

I was trying to work out why you would want to do that when i was reading the subject, after reading your post, you've answered my question.... Thanks

Yes and NO to a point....the Futaba Faast 2.4 is Im pretty sure THE only system you can bind multiple Tx's to a Single Rx and have everything work at the same time.

I don't know much about those transmitters. Do they use modules? If so you could find FM modules and receivers. Then all you have to do is put both tx's on the same channel. Just throwing that out there as a possible option.

I'm not sure about spectrum technology but I don't think you can. If you backwards in technology though and find yourselves some older FM transmitters you can just use 1 RX crystal in your receiver and use the same channel TX crystal in all of your transmitters. You can probably find some older FM sets pretty cheap.

Just to clear things up, after testing last night, it turns out that you CANT bind more than one Tx to the same Rx without having to rebind each time.

I would just run one tx that feels most comfterbale to the team and just swap battery packs.