student visitor question

I am moving to Oxford for a 6 month course in September as a "Student visitor" meaning I have to be out of the UK at the end of the 6 month period. My question is when would I be able to re-enter the UK? I will be applying to three-year programs at theatre schools for the following autumn so will need to know when I am able to return.
Any info would be fabulous. I plan to call WorldBridge (commerical visa office in Ottawa) on Monday but was wondering if anyone had any answers...

many thanks!