The last few days the signal on my Panasonic TV is only about half of what it used to be, this results in the picture breaking up, however, if I unplug the rf in and out and join them together, it works perfectly, so inshort when the recorder is in the aerial loop it ruins the picture, any ideas??

Have you tried a factory reset, or a retune.

I have the aerial plugged in and then watch everything via the hdmi cable on a av channel on a panasonic tv.

There are always going to be some signal losses as it passes through the box … perhaps your aerial / cable has deteriorated?

I’ve not had RF into the tv for years, again we use hdmi.

Do you ever use the tuner on the TV, or do you do select what you’re watching solely using the recorder? If you don’t actually need the TV tuner I’d suggest connecting the two together with something that wasn’t invented in the 1920s.

If you do need it, check the sockets on the box, see if there’s any signs of corrosion (water ingress is a risk from the external cable).