[Resolutionary]

So I went for a brisk drive yesterday and the engine check light came back on.

Same symptoms today but again no noticeable drop in drive-ability. I'm going to see my friend at Tuning Werkes tomorrow afternoon in the hope he can help me diagnose the issues and / or book me in for a proper inspection. I have a bit of a slosh fund ready for the inevitable bills so fingers crossed I can throw money at the situation and it'll improve!

I'll keep you all posted - thanks again for the suggestions.