Don't forget it could have been made by Fraser and then retailed by Holland.

Anyway, it looks Fraserish but I have a Thomas Bland made the same way in 404.

Re the Screw, if you use the correct turn screw, it shouldn't be a problem getting it undone. try some oil / loosener on it.

One thing, if you can find out what "year" it was supposed to have been made, we can then cross check the serial number against the makers and see if it happens to fall in the correct period.

That's just my HO.