Update..... 2 new ride height sensors fitted today.....seems to have cured the problem. Although clean enough to look at, passenger side had nearly siezed up and was very stiff when removed. Also had a bit of a job getting the bolts out and one of them on the trailing arm snapped. Hammered out easily enough and replaced. Next job, another ABS sensor but that's for another day as I've earned a beer now!!
Cheers