The clinical nurse specialist at King’s tells me that I have myelodysplastic syndrome (MDS, www.mdspatientsupport.org.uk/what-is-mds/) as well as the myeloproliferative (MPD) already mentioned. MDS has a number of subdivisions (see en.wikipedia.org/wiki/Myelodysplastic_syndrome), of which RARS-t in the WHO classification seems to match the symptoms best. This has the best prognosis of the lot, with an average life expectancy of 3-5 years. The article doesn’t say how long patients can expect to continue functioning more or less normally.
Its a mystery why the consultant didn't mention this when I saw her the Friday before last.