If you haven't already, try speaking to the management of the leisure centre to see if they'll intervene.
Gemini will probably reject your appeal, and being an IPC member, the IAS (which is the second stage of appeal) are largely useless, after which point it'd be a case of waiting to see if they escalate to court - if they did you'd have at least one avenue of defence, as explained by b789 above, but if you can avoid the hassle altogether by getting the leisure centre to cancel it, this is generally preferable.