For drainage Si can you go straight into the main sewerage if not can you drop a tank in that can be sucked out like an elson a soakaway will stink in the summer and draw flies.
For the kennels themselves wood cabins are a lot warmer I never use bedding,build it on top of a good pallet base ,that will keep it out of the wet ,I tend to then cover the wood in thin steel sheet stops the dogs from chewing the wood,put a kick board in the doorway keeps draughts of the dogs back,will put up photos when I got time.