2011 Fiat Panda. Current battery is an Exide 12v40AH. (original battery?)

When starting car from cold the car starts OK with not much cranking but often the dash clock time resets to 0 and there is a rattle behind the dash/console on the Right Hand Side - perhaps a relay clicking in and out several times ? This happens almost every time first time each day but seems to be cold weather related as it did it twice last winter but almost every time this winter. The car can stand several days without use. After a journey when I restart the car to return home the clock retains its time.

I have checked battery voltages and the battery after the car has been standing over 24 hours read 12.5 volts (no load) which dropped to just over 11 volts when tested again with ignition on and headlights on for 30 seconds. After starting the engine i get around 14 volts. I am using an old multimeter (non electronic display). Starting the engine the meter dips below 10 volts momentarily.

Should I get the battery replaced or is there something else I should look at or test first? The voltages seem OK to me, but is the battery marginal? If the battery are there any make recommendations fior long life? Costs seem to very between £50 and £150. Car is not Start Stop.

Thanks