Ria, I think that M is on a sticky wicket, here. I agree that the landlord should provide the tools but it is up to the tenant to maintain as far as possible, unless otherwise stated.
The original work might have been done to a poor standard but as soon as it started to deteriorate M should have been on to the landlord to point it out. This is going to take a lot of diplomacy and some give and take - on both sides.
My initial choice would be to do it face to face with the landlord, if at all possible, and leave the agents out of the loop. It is how I work with my landlord and it has saved us a lot of grief, stress and money - she pays and I pay, she saves and so do I. Seventeen years we have been at it.