Sophie
I'm afraid you need to participate.
At the moment you are being treated as having Limited Capability for Work until it has been determined that you actually have LCW and an award is made, even then, if it is only an LCW award you will still be expected to participate in Work Related Activity in anticipation of your being well enough to return to work at some time in the future.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems