ok I think I'm going to just got for 25mm at back and 20mm at front, measured the gap last night and there is much more a gap at the abck than at the front anyway so in the end sdhould even things out nicely.
Next question...
With the Eibach spacer there are different 'systems'. Now, I want the most simplist to use and from what I gather this is the system 4's - is that correct?