Just wanted to share what I've been using for front lower spring retainers. This would work for rear lower as well.
These fit a Rover coil(not 110/130) perfectly.
I drilled two holes in mine the same as the spring perch. Slide the retainer into the spring and put the bolts in somewhat loosely. Take weight off the axle(jackstand under frame/bottle jack under axle) and spin the spring by hand until the retainer is "threaded" all the way down. Tighten up the bolts. Done.