Fingers crossed for ya mate!
I had this problem until I found a good MOT tester!
Well, after sweet talking the MOT tester he agreed to put it on the tester without logging it to see if it would pass and if it did then he would run the MOT to save me from having a retest.
So good news and bad news
Good news is it passed with flying colours, bad news is ive just forked out £200 for the tax

He mentioned that cause of the back box i have is a performance exhaust sometimes the readings go to pot, so he blocked one of the pipes (twin pipe) and the readings came down.
Thank god for that, thanks for all your help guys, ive learnt a fair bit about cars in the last week..