Sadly it does look as if that may be the case.
The three freighters have not flown for a few of months and of the two passenger aircraft only G-JOTS has been in service recently, with G-JOTR seemingly out of service at Cranfield. Five days ago 'TS also positioned to Cranfield. Last July they had said they wanted to rebrand themselves as a passenger charter airline with "narrow body" aircraft for independent tour operators but maybe the continued uncertainties in the market made it too difficult to obtain the necessary new investment.
Stobart seemed to feel that they were of no value to SEN and the operational strictures there had caused them to decamp to Biggin Hill.