If this case succeeds in creating a "case by case" rule based on individuals and not situations*, then rugby organisations that do let transwomen play women's rugby will have to have all female players sign a disclaimer similar to that which World Rugby demands of transgender men who play men's rugby.
Something like:
"Written acknowledgement and acceptance by the player of the associated risks of playing contact rugby with transgender women who are biologically male and statistically likely to be stronger, faster and heavier than them, given the predictions this combination of variables makes for injury risk".
*IANAL but I've read that in the Equality Act "case by case" refers to situations not individuals, so that there can be blanket exceptions applicable to a group.