Very common IMA battery badly out of balance due to storage.
3 months is a bad length of storage time.
Cells will be all over the place.
You need a grid charger really to recover it properly. (A cycler is even better)
If you don't use one you risk damaging the battery and it dying quickly as you abuse the out of balance cells.
Sadly the car does not have the capability of recovering properly on it's own.
Time for a trip to Hull if you don't have a charger already..