We have told the staff when we booked the appointment that we are intending to marry in Lytham. And I do not think they have a problem with it. They did not say that the MARRIAGE HAS TO TAKE PLACE IN A DESIGNATED PLACE ---they just have a DESIGNATED PLACE FOR BOOKING AN APPOINTMENT TO GIVE NOTICE TO MARRY. as quoted from your source.. "If one or both of you are foreign nationals and subject to immigration control you have to give notice at a designated register office able to take notices for foreign nationals."
Thanks for the help Iani... are you in Hali also?