I would suggest you contact your solicitor and instruct him to not complete on your home until your snagging inspection has been carried out. I would also suggest you inform Redrow that if they do not allow you to have your nerw home properly inspected, you will definitely be giving Redrow a bad 8-week survey score with a "NO" response to question 1!
I find this inexplicable why a house builder or their site management, would choose to refuse access, in the full and certain knowledge that remedial works will be required after you move in, involving access arrangements and protection of carpets and your belongs (that is if they even think of this!) making the works more difficult for them and definitely more inconvenient for you. They are also creating a dispute with you, making you unhappy, before you even move in
You also have to ask why are they so against it? Your snagging inspector is in fact doing their job for them!
If the home is good and 100% finished what have they got to hide? Are they ashamed of the homes they build that they don't want a professional to inspect them until they have all of your money?
It could be argued that requirement 5.2 of the CCHB is for "disputes" but you will be in dispute if they do not allow you to check you home. Redrow are being unreasonable but
builder refusal is far too common.Most snagging inspectors I know come across this every week. Even so, it is still well worth getting your new home properly checked and inspected, even after moving in.