It is very important to organise trades before you need them.
This way when water is coming through your ceiling you know the right person to call in an emergency. It’s important to speak to the company to find out what sort of qualifications the engineers have and to make sure they all have insurance.
Some companies will give a guarantee on all the work carried out this is very important to find out. Not all companies carry parts on board their vans so try to make sure that the company you choose does.