Damp proofing/tanking repair - Damp Proofing job in Shadwell, East London

Job Description

I have a patch of damp in a basement wall - all other basement walls are fine .
I am unsure whether this is cause by cracks in the pavement cement render around the front door or by the 30 year old bituminous tanking breaking down or both.
I need advice from a knowledgeable damp proofing specialist as to the cause of this damp and then repairs made to the pavement render, damp plasterwork and possibly tanking -
It will require a site visit to advise and quote