Graham,
Changing to diseqc A results in full strength and the receiver performs ok but it doesn't retain the changed setting. It always reverts to Freesat and LNB tather than diseqc A.
I've persevered with this issue and have had a degree of success. In non-FS mode I can change to Diseqc B & Astra 1 and download channels that I want. Interestingly after selecting the combination of switch input and satellite there's a bar graph for signal strength and it indicates no signal but the next step scans and dowmloads loads of channels---so there is obviously signal. In fact once I'm viewing in non-FS mode and go to settings / signal strenght it shows a 90% signal. When I switch back to Freesat mode all works OK.
There does seem to be a problem with receiving Hotbird. Selecting Diseqc C and Hotbird the receiver is not seeing anything whch makes me suspect that the switch isn't workign on this port. I think Repassac suggested in an earlier post that there may be a problem with the switch. If I try and save this scan then it all goes wrong and switching back to Freesat the receiver then gives the indication of weak signal. So we'll live without Hotbird until I can replace the switch.
Thanks for all the replies on this matter.
Geoff