Being fairly new to towing an Eriba my car manual says to inflate the rear tyres to full load pressure, but does anyone deflate the tyres to normal pressure in between towing trips?

Yes, I return to normal pressure if I am on site for more than 7 days and always between trips.

Stewart

Hi
I always return the tyre pressures to those recommended by the manufacturer for solo running.
Then there's that old problem of how good is your tyre gauge.
Best regards
Tom

Just be aware some vehicles have towing pressures as well as full load pressure. Some are similar but some cars are hugely different + if possible check tyre pressures when they're cold