2006 is in the era when the factory rear springs were of very poor quality, seems to have started around 2005 (ish) and gone on until 200* (ish) nothing is finite dates with Morgan. My 2008 4 seater had 3 sets of springs under warranty until the factory changed supplier and they were fine after that. I am afraid new springs is the answer, as the OE U bolts are very poor and soft as carrots it's a perfect time to upgrade to a set of Mulfab U Bolts and Spring plates, takes no extra labour to fit them other than cutting the bolts to length so well worth doing whilst it's all apart. Having done a set on my current 2 seater I would say it's a physically tough job, not complex but without a good trolley Jack and decent axle stands might be a lot less hassle to book it in to a dealer, the job is far simpler with a car ramp.
