Transfer of bought council house

I bought my council house outright 23 years ago .

I wish to " transfer not for value" it over to my son

In the land certificate it mentions a restrictive covenant
about repaying to the council the reduction i recieved on the
house price when i bought it in 1990,but in reading
the certificate further that was only if i sold/transfered the
house within 3 years.
Does this sound correct and do i need to go to the council
before submitting my transfer forms to the land registry.

Thank you