Visa options.

Hello there! I've recently applied for a Prospective student visa as I'm scheduled to attend a few interviews at certain universities in the UK.I'm looking to enroll myself on a full-time post graduate course.

I am aware of the fact that I need to apply for a Tier 4 (student) visa should I be given an unconditional offer from a University. My query has to do with what my options are should I choose to do a short course (3 months) that immediately precedes my full time course.The short course would end 2 weeks before the full-time post graduate course commences. Moreover, the short course is not a foundation course nor is it provided by the institution where I'm to do my post-graduate studies. The short course content, however, does relate to the post graduate course subject wise and in essence could be considered preparatory to it. The prospective visa, if granted, will terminate well before commencement of either course as I have applied for the post-graduate course well in advance.

So essentially, I won't be able to use the prospective student visa to change over to a Tier 4 visa as it will be too early in the year. Furthermore, if I consider a student visitor visa for the short course, stipulations say I MUST leave the UK at the end of the duration of that visa and re-apply for entry in to the UK, which is impractical when considering the short amount of time between the termination of the short course and commencement of the full-time programme.

Are there any options for a visa application I haven't considered? Would I be able to apply for a prospective student once again for the short course? I would appreciate any guidance.