You got your head job done at a good price, don't let anybody tell you otherwise. £300 sounds like it was done as a 'side job', while this is cheaper it is always a more risky way of having stuff done, - where is the garantee if some thing goes wrong later on? What quality where the parts?
Certainly no need to go to Renault dealer for a Clio 1, they are a good car with nothing over complicated on - find a local garage that has a good reputation and stick to them, if you do have any problems with anything they have done you can go back to them and they should look after you.
As for that comment about labour rates, have you had a look at the price of property or rental cost for workshops, never mind the cost of employing a 'good' mechanic!
It always amazes me how people will pay loads of money to have a guy come to look at the washing machine and say ooh I dunno guv, cars are far more complex - with several computers on now, you need them to get about, and you depend on them being in good order not to kill or injure you.
Anyway off my soapbox now.