...the right to practice religion is a qualified right and not an absolute right, meaning, it is limited in scope and not an absolute. This means the courts can limit its use to protect the interests of others [wide]. The others can include the Gurdwara, for example. Under article 9 of the HRA 1998 the courts will do all they can to allow the individual to practice his/her right provided there are no overriding considerations [OC]. In this case there are OC because the Gurdwara, seen as an institution, is protesting to protect the tenets of its faith, namely, Anand Karaj [AK]. That is to say, it can only be performed by two Sikhs [SRM, definition]. The courts are obliged under limb 2 of article 9 to exercise caution, necessary in a democratic society. They will curtail the right of the individual to strike the right balance between the two. This would mean a marriage can be had at a Gurdwara, but not AK if Gurdwara objects.
In seeking an answer the right question to ask would be, what is the role and responsibility of the institution [Gurdwara], is it to protect n preserve the tenets of its faith or the welfare of its members ?