I think this has had a good airing on other threads already. Without manufacturer support, it can't continue to fly. If the mega amounts of money needed to secure such support could be found, the whole fleet could carry on in revenue-earning service.
As the aeroplane ages, support gets more expensive and parts harder to source. Add to this the grounding of the AF fleet, and that leaves BA to pick up the entire cost of such ongoing support. I suspect the sums just don't add up for such a small fleet.
AFAIK there is no 'cheap' half-way-house which would just keep one Conc flying. Unfortunatly.
SSD