Thanks for the reply's i think i will put on another super
To clarify the 12x14 is full off bees and they have put a lot of stores in certainly enough for a normal winter in addition they have also filled a super and are now bursting for more room and yesterday they were all out flying
Don't put another empty box on top!
A better route would be to put your extra box UNDER the brood (no Queen Excluder). Search the forum for the word 'nadir'.
Unless you are VERY strong, you should enlist some help to lift the well-filled 14x12 brood box. They are
heavy.
I would suggest harvesting your full super if it is capped. Put a clearing board under it (above the brood) to empty it of bees.
Since much of the honey will likely be from Ivy, you should extract it asap after removing it from the hive. My suggestion would be that you keep it in a small honey bucket, jarring only a couple of jars for personal tasting and watching the state of crystallisation.
Ivy honey tastes better after it has been stored for a while.
If your super is
uncapped, you have two principal options (no need to clear it first). Firstly to nadir it (I'd put it directly under the brood) so the bees will concentrate it for storage as they move it up into the brood box before winter. The second option would be to extract it, and store the too-wet honey in the freezer until you have the opportunity to feed it back to the bees (freezing should prevent fermentation).
A third option would be to make mead - but I'm not sure Ivy honey would be the best starting point!
If the super is uncapped and you nadir it then its your call as to whether a second nadir (below it) is really needed.
But sticking an extra super on top, in mid-October (even in tropical Somerset) is unlikely to be the best plan.