Obviously access is always an issue but as mike suggested removing the driveshafts allows much better access. I found that once the discs had been removed I could then wiggle and twist the caliper out without having to remove or lower anything else other than the handbrake linkages. I think it may be worth your while removing the calipers and probably giving them an overhaul as they tend to get neglected, if beyond repair you can just replace them for reconditioned ones. I removed both my rear calipers and discs last year, refurbished one caliper and replaced the other with a 'new' one and fitted brand new discs. Once you have had a good look at the setup it is actually very simple to work on, as I say you just need good access.
Mike