Apologies for slow reply - we had a severe storm with off-on-off-on power cuts, which bricked my HDD and flooded a poe extender (allegedly waterproof). Luckily PC and NAS are on UPS. Only just back on line again.
Thanks for the info - sorry I thought I had stated the current firmware version, which is old.... V4.30.005 build 200628, but I see that in fact I missed that vital piece of data from my initial post. My concern is that firmware versions for the KB92 platform start at V4.31.102 build210626, where the K74 starts at v3.4.112 then jump straight to V4.30.010 E-UI and up to V4.30.085. I don't know the extent of changes between the K74 and K9B2 platforms, but I strongly suspect that the firmwares are not compatible... However, Hikvision's model numbers are somewhat obscure - if there was a major change between platforms, why not change the designator from C to D? Any further advice would be gratefully received, but I think I am going to have to work through the K74 set, and stop there. Thanks