Thank you. In my case, of course, it's the rear RockShox Deluxe that is the issue. I've found some helpful documents on the RockShox/SRAM site, although not one for that 1999 model - and they seem to have used that Deluxe name over many years, so there are lots of PDFs around for the wrong ones. Surely someone somewhere must have the right PDF?
On closer inspection, I've noticed that there's a collar that seems to have come unscrewed (the black one in the middle of the picture below, just where the piston emerges from the housing). Not sure whether that means it's a write-off and I need a new unit. But, by the same token, I've realised that the spring is integral to the unit, so getting the unit out looks quite straightforward. It's what I do next that I still have to work out. And whether a generic set of suspension tools will be helpful assuming I can save the existing unit, not to mention whether spare seals etc. are available anywhere!
