Can I use the existing valve on my current airbeam on a new airbeam? I have a front beam which collapses in the wind so looking to replace but i see this beam does not come with a valve.

Yes, I can confirm that you are able to take the valve off your old tube and use it on the replacement (providing the valve is in working order).

You should be able to simiply unscrew the valve from the tube and re-screw it onto the replacement.