The Sabre was produced under a rather (we need it mentality) and never really sorted when it entered service. Like most very complex and complicated engines HOW it was operated also makes a substantial contribution to keeping it serviceable. Given the advances in cnc type production quality and the knowledge that this is not an engine for rapid throttle movements the challenge is how much 'out of the box thinking' will help enable the 'reliability factor' to be improved. Bringing in expertise from todays top racing guys could really help with this. For myself I only had exhaust valve issues, but sleeve vales did live on in later engines, and I suspect that the older technology could be improved enough to keep an example running good enough for demo purposes. They may have to be carefully 'warmed up' and power fed in smoothly, but then that is all part of keeping history alive as opposed to just being a static exhibit. Lots of interesting comments on the Sabre story in Rod Banks book plus the comments that despite all the problems and production issues (with engine and airframe) their part in the Normandy campaign justified the effort (just). Of course in Normandy they also had to contend with sucking in a very damaging dust before being retrofitted with better filters. The average Typhoon 'life' was such that the engines never really gained much of a chance to be improved by strip down inspections. They certainly are not a jump in pull the choke and shoot off type.
The engine ended up in Target tugs at Sylt so must have had some sort of serviceability rate for that job.