Nope, you were right! 20" trials bike = mod
P.S. There really is no point in spending £320 (presuming you'll buy first hand from TartyBikes) on a 2010 Onza Rip; you'll be better off waiting until you're validated and purchasing a second hand bike from here or buying one on eBay - you'll get a much nicer bike for your money. Not to mention the fact that they're f**king ugly.