As prequels go it was very good.
The comedy drama format that was used as opposed to the sitcom format they might have used worked much better, had it been played for laughs with the new cast doing impersonations of original cast it would have failed I think.
Also having the story based on Reg, Joan and Freddie (omg thats a bit Rainbowish) instead of Del and his mates worked better.
I enjoyed it, but I can't agree with what some have said about it becoming a regular series, yes it has potential, but we all know the history, Reg buggers off, Joan Dies and Freddie does a job that goes wrong and dies also. That story can continue in a couple more specials but no more than that.
I've been a fan of Kellie Bright ever since she was in The upper hand and I really enjoyed her in this, also I quite like Phil Daniels too.