I think more important than 'who' is 'where?' There are no suitable sites left within a realistic distance of Plymouth - even Sherford wasn't ideal as aircraft would still be overflying the city.
As well as the volcanic ash, Plymouth spent a good deal of time shut this winter. Purchasing several full tanker loads of de-icer and other equipment to try and get the runway/aircraft operational again can't have been cheap for SHH.
The transport division lost £1.49 million in the 6 months to September 2009, pitched against a profit for the same period in 2008 of £274,000. As far as I'm aware, the carrier was consistently profitable before this after the initial set up period. They are in a fairly good position even now, with almost £17 million in assets.