I do have a 218 but it is not currently in my system (I thought it might be faulty) so thank you for your suggestion which I will bear in mind for the future. I am suspicious of my 271, but given that I seem not to be alone perhaps either we both have defective 271s or there is a firmware defect. The latter is more likely but, since repairing electronics at component level is my hobby, when I have time after Christmas (and Jury service in January) I will take the 271 out of its rack and check it over. It would not be the first piece of Meridian kit that I have had that needs attention. Unfortunately, I can’t fix modern software (it was 1967 when I last did any programming (Fortran!).

Cinema/Music: Trinnov Altitude32 8-16,218,Cloud 4 channel, Marantz UD5007,DSP5200SE(2+C),DSP3300(4),DSW(2),271,MShort Ceilings,AppleTV 4K
TV: Marantz SR7013 Wharfedale Diamond 9x4+Celestion(C)
Music: Roon,i7NUC8gen,QNAP TS253A, Sony Scala, MS200, Garrard DDQ650,Wharfedale Diamond 12.3
Kitchen: AD88 (bluetooth via i80).