URGENT HELP NEEDED - Leaking barrel

[MARMITE]

I've set up a pin of bitter for a CBA meeting in 3 weeks time .No problems with warm conditioning but 2 days ago I put it in my larder fridge with the intention of cool conditioning at 12c. Unfortunately I didn't set the temperature correctly and it stayed at 5C , which I use for lagering. I rectified this in 24hrs and it's now back at 12C. However this morning I noticed I have a leak from the bung hole. I have weighed the barrel and compared this to an identical barrel filled with water. There is a 4lb difference so I reckon I have lost about 3 pints.

What do I do now?? Do I
1) Live with it and hope it turns out ok? or
2) Reprime adding a bit of fresh yeast to restore any lost condition?
3) I have 4 spare bottles of the same beer - so I could gently pour some in to restore the lost volume and again reprime adding a bit of fresh yeast.

I would be grateful for any suggestions - and by the way I have wacked the bung in harder now!!