Tier 4 visa extension without progress on current visa

Hello guys ,

I need some help for my visa extension.
Came to UK on level 5 for ACCA course on 09/09 (visa till 04/13)
Applied visa for 6 months on 03/13 to continue ACCA (CAS issued for level 7)as I was left with few papers then, got visa till 10/13.
Applied visa again for level 7 advance diploma in marketing management and got visa till 08/15.
Now I want to study MBA as I finished my ACCA.
But the problem is I don't have any progress on my current visa.( though I have passed 2 ACCA final papers and submitted a research report to Oxford Brookes University in order to get BSc hons degree).

I have already got an unconditional offer letter from university for MBA october 2014 intake.
I am worried about my chance to get visa for level 7 again without progress in current visa. Anybody gone through same situation?
Please need some help!!

Any one there?
Please help me!