Home DIY

We have some condensation issues in our main bathroom...

Multiple causes:

1. Outside wall (1930s house so air gap only?)
   
2. Rain shower dispenses lots of water which means lots of steam
   
3. Washing machine / condenser tumble dryer in there too
   
   

It's double glazed at least but still...

The fan is small and runs off the light ring (I assume... As it turns on with the lights).

Couple of questions:

1. Can I upgrade it without making a bigger hole?
   
2. Will that really make much of a difference?
   
3. If I clean out the one I have, will i see a performance increase?
   
4. Is it likely the one I have has adjustable timing and will elongating it actually make a difference?
   
   

This is the one I have: