I have borrowed the below text from another thread on the forum as it is super applicable here.
Good work RFT, many thanks and all credit due for your efforts in getting this issue onto the right desks at MBUK.

Mega Work!!
"As promised I have now spoken to Rob Halloway who is Marketing Director at MB, on the board and reports directly to the UK CEO. He was joined on the call by Sam Johnson who is the Customer Assistance Manager and who heads the department that deals with escalation of problems. Neither claimed any knowledge of our roof blister problem.
My roof was last replaced in January, with one with a serial number, and so I'm hopeful that this latest iteration of roof will sort my own problem. However, I made it very clear that inside or outside the 3 year warranty, roofs need to be replaced until the problem is finally fixed.
I would recommend that everyone emails MB with their own story, whether they are in warranty and having knock back from their dealer, out of warranty and have had their claim kicked out or currently problem free (like me) but registering their concern that their current roof may not be any better than their previous roof.
I specifically requested that a specific person be nominated at MB to be their point man and I was disappointed that after the call I was given by text what looks like a generic email address me but advised that it was not generic! Whether you have used the email below previously or not
please refer to the Marco Polo roof matter that has been discussed with Rob Halloway and Sam Johnson.
If you still receive a less than helpful reply that looks as though it has not been escalated please tell me and once I have a handful I will tell Rob and Sam that their suggestion hasn't worked and if they then fail to take appropriate action I will release their email addresses and direct numbers.
Obviously the more people that email with their concerns the better:
[email protected]"