In a time when the NHS is struggling beyond belief should gender/sex even be considered is a bigger question. What if the HCP hasn't declared their sex assigned at birth to fellow staff, by forcing them to declare it to patients is outing them.
Personally I don't think gender, race, religion etc should be considered in NHS care. Whoever is the most appropriate HCP provides the care. In time if and when NHS waiting lists have recovered and the service is funded properly then luxuries like this can be considered.