We've got dry rot under our stairs.

A company has been round and told us that all the floorboards in hall
will need replacing with treated floorboards. Plaster will need
replacing to height of 1 metre (up to Dado rail) by 3 metres wide. Two
air bricks will need installing.

The quote has come in at £3000 for a weeks work.

This seems fairly expensive considering the quote effectively covers

1) what the cost of floorboards are (hallway measures 2 metres by 6)
2) 2 people for 2 days to lay floorboards
3) install 2 airbricks (cover one exisitng air brick which is level
with pavement outside (this is where water has been coming into the
house)
4) the cost of a plasterer for a day and his material.
5) treating all new wood with dry rot prevention chemicals
6) finsihing work

Can anyone recommend any companies in North Manchester/Bury area which
deal in this type of work?

Regards