Deed of release of restrictive covenant

A restrictive covenant is listed on the title deeds of my property requiring it to be kept as a 3 bed house with a garage (among other things). I have a signed deed of release of restrictive covenant confirming the consent of the beneficiaries to vary the restrictive covenant so as to allow the garage to be converted. Please could you confirm which form is needed to register the deed of release with the Land Registry? Many thanks 

Natasha - form AP1 - Change the register (AP1) - GOV.UK