I can maintain a stall quite well, but nearly every time I try and Axel I get a wing tip wrap - any ideas what could be causing this?
When starting out, it is easier to do axels if you start with the kite not pointing straight up. In other words, stall the kite with one wingtip slightly higher than the other.
If you imagine your kite's nose points to a number on the clock, it usually points to 12 o'clock when stalled. To practice axels, stall the kite with the nose pointing to 11 o'clock or 1 o'clock. Now you will have one wing tip higher than the other. Pop the higher wingtip.
This gives the higher wingtip the space to rotate around without crossing the path of the opposite flying line.
You might find it easier to achieve this at the edge of the wind. Try flying out to one side, and as the kite loses pull turn the kite upwards. Keep the turn going until the nose of the kite has passed the 12 o'clock position, then pop on the line nearest the edge of the wind
And importantly, like the other guys say, make sure you give it slack while the kite is rotating