Cyril was worked at Atlantic Motors. He made frames with skill. It looks like a nice bike. It should have an aluminum tank, regardless of the tank coating. The F106 is missing and it has been replaced by some tubing. I don't think that is too much of a worry.
The Burman box and clutch is not my cup of tea. I would have thought for the price it would be a Commando box with a Newby belt drive. The pipe is small and straight, which could be good and bad. Small can be good, but loud is bad. If you are running it on the street It should have a silencer of some type.
Just the few parts I have mentioned would add up to quite a bit of money and I have not mentioned the top of the line version of those parts.
David