Have a look at the Kent and Masters website. I have their GP cob saddle and hope to get the dressage one in the future. They are great as the gullets are changeable so you can keep the same saddle even if your horse changes shape.
I have the thorowgood T6 dressage saddle and I have found it very comfortable, the gullet can be changed as your horse changes shape. Maybe worth you having a look.
Another K&M vote, I have the Cob GP, which fitted my oddly cob-shaped TBX beautifully. It's a very nice saddle, and was reasonably priced. The cob dressage version looks lovely.