Friend of Mike mine runs Entertain Wirral, does all sorts of packages including Lemon Echo covers band...https://www.facebook.com/EntertainWirral
some more friends have a soul/funk band called Hotel Sleazy. They're playing Sheridans this Staurday if you want to audition them. Guitarist Terry seems to do most of the promotion...https://www.facebook.com/HotelSleazy
and more friends in local indie covers band Sugar Shed, been known to take the odd wedding booking. Bassist Iain is the sensible one..https://www.facebook.com/SugarShed
TBH if you're out and about and see a band you like, don't be shy just go up and ask them about it. The worst they will say is "no thanks". Good luck for your wedding.