C30 Engine : C30 D5 manual. Undiagnosed Limp mode

[C30Phil]

Hello guys.
Basically I'm having an issue with my 2009 c30 D5. I've had this car for 3-4 months and it kept going into limp mode with a generic reader it came up with MAF and MAP sensor. Originally I reset the codes once a day for a week so it would come out of limp whilst the new MAP and MAF sensors arrived. changed them and the same issue is happening. whilst coming off a slip road onto the M4 my boost pipe gave way (jubilee was more than likely old) and I managed to get it on briefly and drove to my friends garage so he could sort it properly. got it to my friends reputable garage and asked if he could change the belt(it was squeeky) and if he could diagnose the boost leak/limp mode problem. He tried and couldn't diagnose and now it never comes out of limp mode, even when reset. he asked a volvo specialist to come in and also couldn't diagnose the problem and now I've bought VidaDice. what would be my next step in finding what's going on?
My battery also died in my friends garage and the SRS and airbag light is on. Vida says change the SRS unit. but gives me no Codes for the limp mode issue.
If anyone could help me that would be great! would love to keep this Volvo instead of scrapping it!