Hi Mark, nice to see another chub fan from Oxfordshire! I'm in abingdon, so spend most of the (unfortunately rare) sessions at this time of year on the Thames here... one of the things I like most about this part of the season is that if you can only get an hour or two on the bank, a big chub might still play ball and make the trip worthwhile.
As for baits, I have to confess to being something of a conservative... generally, I either leger flake, with liquidised bread in an open feeder - or straight leger a lump of cheesepaste.
On the days when they want it, the cheesepaste is definitely the superiour bait in terms of the bites it produces. I've had sessions where pellets, worms and bread have all received plucks and bangs with nothing to connect with.. on changing to cheesepaste, the bite becomes unmissable (it's hard to miss the rod being dragged off the rest in to the river). I've been fortunate to catch a few real clonkers (up to 6lb 8oz) but the dream of a 7 keeps me going back.
The cheesepaste I use is based on ready made short crust pastry, with equal ammounts of grated cheddar and crumbled danish blue kneaded into it. My hook-up rate improved dramatically when I switched to the pastry mix (previously the base I used was liquidised bread), the pastry mix has a really nice elasticity to it which stays on the hook very well but seems to be easy to strike through.
I'm all ears about additives, my only problem is how to judge how well the additive has worked... I'm lucky to get out for a couple of hours every other week, the river conditions change a great deal in that time so results from one session to another could have just as much to do with changed river/ weather conditions as they have with the new bait mix, spose you need to take several mixes and give them a go.
Great thread, hope there's more to come from others on their bait secrets!!
Jim