Looking for a little help

My travel insurance policy (First Direct)states that it covers mountain biking as follows:

“Downhill grades 1 or 2 only (or the equivalent international grade used by the country you are in). No freeriding, four-cross, dirt jumping or trials”.

I don’t know about you but this is a new one on me, has anyone ever come across downhill levels 1 and 2 or have any idea what grading system they might be on about? I can’t find any recognised or widely used grading system that uses this numbered system.

I have written to the the insurance company for clarification button heard back yet.

Any ideas?