Hopefully you’ve seen our UK/EU calendar : BBB.gd/calendar there’s a map function, robodojo near York is probably your best bet for ants in the north east.
Weight on ants is tight yep so a lot of people go 2wd to armour up more.
Servos are often used for flippers because they have a set range that’s controllable on the stick, brushed motors will spin until you center the stick or stall out. There’s pros and cons to both. You’d want a low rpm motor for a flipper to have enough torque to throw 
Mechanisms for ant flippers are usually linkages a bit like this excellent diagram from Shakey:
