Finally, after a lot of noodle scratching I decided that rather than put this together myself and risk burning down the house I'd try and find someone who knew what they were talking about electricity wise.
I put the feelers out on boards.ie and got a response from a lad who was happy to take a look at it for me.
And then, just like that the job was oxo. Having gone through the intricacies of the build with the guy there was no way I would have been able to do this myself.
As controllers go it's as basic as it gets, it's just a way to control an element but im very happy with the results.
Here's a few pics of how it turned out.
Cheers.
Is that a Temp probe socket in the side?
Yeah, that's for the temp probe. I've done a water test on the system and everything seems to working great.
I never realised how complicated a PID was. I thought it was just a matter of turning it on and away you go.