Unfortunately I've just had this email from them:
"I'm afraid we've just heard that we aren't going to be able to offer storm chasing cover for the foreseeable future. We've just placed a message to this effect on our website.
If you are struggling to find cover from another provider I would suggest contacting a local insurance broker, the British Insurance Broker's Association have a find a broker helpline who can offer assistance in this regard:
http://www.biba.org.uk/
Apologies that we are unable to be of assistance in this instance."
Will try that broker helpline and hope something comes up!