Hi all
Thank you for the feedback. For everyone's benefit, I have now tried TIC, Bytes, Santam, Safetywing, Allianz and they all have the same exclusion, regardless if you are a professional or amateur, if its a mountain biking "competition" its specially excluded. I am also unfortunately not a member with Discovery, I am with another medical aid (CAMAF).
So I am completely stumped now and cannot believe there isn't anyone who would cover this. Any other recommendations would be welcome.