hi I have a 4 ch swann dvr (bnc ) and want to update to an 8 ch (cat5 digital) connection dvr I have seen balun connections etc , would they work to convert my connections ? I don't really want to buy a whole new set of cameras as the 4 I have in place are fine plus its a hastle to re route all the cabling as they are all at a my roof level and cabling is through my loft space . I would just buy 2 new digital dome cameras they will be at lower level i.e door entry height etc. thanks in advance for any help given p.s I'm in the u.k.