Advice needed - what's a reasonable quote to fix damp wall?

[LiverpoolBound]

We've just moved into a new house. No damp was picked up on the survey but since we moved in some damp has appeared and quickly spread across the wall in one of the upstairs bedrooms. We've been given two quotes to fix it - one for £1000 and another for £600 but we've been told by someone else that's its a really small job and they are overcharging to be able to avoid doing the job (a relative, not a builder not capable of fixing it!). We're totally in the dark on anything like this and have no idea what is a reasonable quote. Any help/guidance would be hugely appreciated...

Thanks

 

[Alastairreid]

More info and a pic needed,

 

[Nige F]

We've just moved into a new house. No damp was picked up on the survey but since we moved in some damp has appeared and quickly spread across the wall in one of the upstairs bedrooms. We've been given two quotes to fix it - one for £1000 and another for £600 but we've been told by someone else that's its a really small job and they are overcharging to be able to avoid doing the job (a relative, not a builder not capable of fixing it!). We're totally in the dark on anything like this and have no idea what is a reasonable quote. Any help/guidance would be hugely appreciated...

Thanks

If you really are in London - I`ll come and fix it for £500 And I`ll tell you now for now`t that it`s probably condensation