LSM et al, the UK AIP ENR section can be found
here and section ENR 1.4 ATS Airspace Classification states
ATC instructions are mandatory for any IFR aircraft flying in Classes A to F airspace, and any VFR aircraft flying in Class B or C airspace.
NATS train their controllers to expect everything and anything, and during the emergency simulations for training, sometimes there are examples of emergency descents with no communication and turns. It is well known that no communication is likely in the early stages, all a controller can do is the best they think at the time. If this is expected, then anything else is a bonus, and for me, the biggest bonus would be to squawk 7700. This one thing simply draws the attention of not only the controller working the aircraft, but every other controller with airspace in the vicinity or controllers who are authorised to penetrate CAS without coordination (military etc). As for the turns, they aren't liked in NATSland, but again training covers this. My advice is to be very cautious turning if you have already been assigned a vector, it probably means there is another one not that far away that you might just turn into.