Thanks for your input.. I am a fussy bugger but I actually assumed that with all the hype over the essential mandating of gas safe rgi's, that standards were very high... Needless to say, I've had a rude awakening and now have eroded trust in tradesmen.. Common for me.
Gas Safe Registration is about making sure that the installation is safe and has been properly tested not so much whether the pipework is pretty to look at.
If you are fussy about the 'finish' on the work to be done then you need to see examples (or photographs) of their recent work to check that their normal working standard matches your expectations.