im looking to soften up my 07 sdr as its rock solid and ive also had/got back problems, basically im looking for the best softer set up on my original suspension, its not got to be pinpoint perfect as I don't ride on the limit and only do road ridding, anyone have a record of there soft set up details or recommend anyone that can advise my on a good one, im 13 stone. travel to suspension techy aint an option because of my location, cheers

Your SDR has an orange spring which is a 185 I think. A lot of people change their standard SD White, 175 spring for an orange one or fit a SDR shock for track use. I am 13 stone also and have both shocks. The white spring is a better ride for most British roads and needs to be on nearly maximum preload to get the correct static sag for me in full kit. The 185 SDR needs to be on almost minimum preload to get the same static sag.

So, you could try a used standard SD rear shock or get a white spring and swap it over. They are pretty common place on Ebay.