Brought in in 2004, with debate about implications, it seems to have achieved what it aimed to do.

ie enable "around 5,000" transsexuals to change gender, thereby ameliorating their mental suffering, without having a big impact on society because the numbers were so small. It was recognised to be a fudge, but an appropriate one in demonstrating compassion for those with genuine gender dysphoria. If the numbers had been higher, it would not have passed because the impact on the rest of society would have been regarded as too significant

I think the number is around 4,800. So they got that spot on.