I need a new set of screen screws...I had a look at the ProBolt set but not sure how the big black rubber nut thingy is going to fit...looks rather big to fit through the screen holes or am I being thick?

if using a non standard kit then yes you need to drill the holes a bit bigger to get them to fit
the genuine kit if i recall for the RC30 / NC30 was only around £6 if i remember right and they are like a one way clip like standard

Believe it or not i'v just got some off e-bay they came all the way from Germany they were a good price & quality as you'd expect from the Germans check them out @ http://www.tankpads.de" onclick="window.open(this.href);return false;