On Wednesday, April 22, 2020 at 2:26:48 PM UTC+1, wrote:
There is no obvious need to switch the power between charge and the
sockets?

I know very little about solar PV. I considered that an appliance drawing more power than the panel could supply might harm the panel, so I thought it best to switch the panel out of the circuit to ensure power was only ever drawn form the battery.

If I were considering doing this, I would be installing a mains powered
12v (13.8v) SMPSU - do you not have any mains power in the garage?

I do have mains power in the garage. I will look into this solution, seems to be neather than my proposed solution!

Thanks