If you have bought redcurrants and raspberries, IMHO they aren't suitable for training as espaliers. I'd put them into the soil now rather than in pots. Don't put your fruit too close to your fence, as they may get too dry there
The redcurrants are unlikely to fruit this year, they may fruit next year depending on size, but you will need to put a net over them to stop the birds eating them!
The raspberries might fruit this year if they are "autumn" fruiting types (which could fruit anytime from late July through to November). If they are "summer" types, they won't fruit this year but will fruit next year.