i would normally say the usual caster worm corn but a lot of bream are being caught on the pellet(halibut 10mm are lethal) and white chocolate mini boilies but in a match i would start on open end feeder filled with a good groundbait half supercup half sensas lake with braseem added is a cracking mix with a few casters and squatts added give the worm the first hour if no response try the pellet
my favorite method is to chuck 5 - 10 feeder loads to a target and fish over the top with quick link feeder / bomb. Use double / triple red maggot, interchange with corn and or worm and caster for good measure. Main advice though is to get a decent "bed" of bait down first and leave for 1/2 hr or hour before fishing. Oh and keep topping the swim regularly. Good Luck for the match mark.