Musty smell in house - would surveyor help?

My grand-aunt lives in a bungalow in the Midlands. It was built around the '70s and she has had it dry-lined and some sort of chemical pumped into the walls. She has central heating but doesn't really like to turn it on as much as I think is necessary. She does not open doors or windows very often as she is nervous of burglars as unfortunately a lot of people her age are. She does however have vents in all the rooms that she keeps open all the time so that there is a draught even when the heat is on. There is an awful smell of damp (I think) in the house, if I bring any clothes down, even if they don't leave the suitcase, they have to be washed when I get back home as there would be a musty smell off them. At the moment she also has a problem with woodlice.

My query is - is there some sort of a surveyor I could get to have a look at her house and identify what is causing the smell? Can anyone recommend someone they have used before? Or any other solution?

It sounds to me that you have probably already identified the problems - lack of ventilation and inadequate heating. You should also check for any obvious leaks (blocked guttering or similar problems). I have 2 suggestions: see if she would consider leaving the heating on permanently on the lowest setting, secondly see if it is possible to lock some of the windows open to increase the ventilation. Woodlice are not much of a problem, but they do indicate dampness, get rid of the damp and the woodlice will go too.