Did solicitor advise you not to get full report in writing?

Is it a new build?

A home report should have looked at the roof trusses. The surveyor likely has photographic evidence. Beware this might implicate your builder in sabotage.
Personally I think your first call should be to your surveyor to see if the house is in the same condition as when surveyed.

The property isn't a new build, the original part of the property is 1930s, and then it has had a couple of extensions and then changed from flat to pitched roof.

The house isn't a new build

The property will be as surveyed, as the trusses have been cut to allow full head height above the garage(attached to the house), and was advertised as accomodation above the garage space

Then the poorly built part is above the main house where my builder who was round looking at something else has pointed out the deflection he can see in the rafters where he said they should be doubled up and have webs installed (some are there but incorrectly placed and/or build onto non solid structure - onto the felt roof and not onto the joists themself)

Really starting to make me feel I've paid a lot of money for a property that isn't worth what I've paid and requires a lot to be spent on it...

and sorry, yeah victoria, I have it in writing, when I asked if I should get a full survey due to stuff being missed in the initial home report she said "I don’t think that a further survey would tell you anymore that the home report. Whilst the Home Report is not truly independent it is prepared with the buyer in mind as you can sure the surveyor if there is anything in the home report which a reasonable surveyor would or should have picked up."