i use www.speedtest.bbmax.co.uk, it says it only goes upto ten meg but im on 20meg and it shows my results fine. Usually achieve 16000 - 17000kbs
I'm with virgin and in the past i have been the first to slag them off and get my internet discounted for 1 year but lately they have actually improved a lot. I used to get 2/3mb or 6/7mb ten mins later a 20 meg account. But the last few months have been constantly high results. Probably due to the imminent launch of the 50mb package.
just thought i'd share that with you