wireing help fuse spur for boiler with supply ,inside back box not yet connected 3 core and earth goes to stat.inside boiler connection plug live neutral earth 1 and 2 currently with a link in, presuming i take a 5 core flex between the 2 how would i connect up firstly in spur and then at boiler,any help appreciated thanks boiler being operated manualy at mo.just a thaught would the brown from the 3 core go with the brown from the flex on the outgoing side of the spur and then black and grey in terconected withe the same on the flex,then at the boiler black and grey in 1 and 2 hope this makes sense thanks anyone