Hello - thanks to all for contributions

The Marriage was indeed 1892 - have become obsessed with 1891!!
The 1871 census spot (thanks for checking Birket St, JenB) was really helpful as Margaret is my GG Grandmother and was not sure if she was born to Thomas Trewick (Margaret's first husband) or Peter Brunton. The census points to 1864/5 and now I have the baptism record off Fam search of Sep 1864 with Peter as father. Thomas Trewick death was 1862 so I think Peter Brunton is my GG Grandfather - and Margaret was the first of his 19 children by 2 wives!
Have been in touch with Register Office but no birth record for 1863-66 - thought might not have been registered if Margaret & Peter not married.
Can anyone find birth (Margaret) or marriage (Peter BRUNTON & Margaret TREWICK/HESLOP 1862 onwards)?