You can do open water combined with drysuit. in the UK, it's the norm with most schools. Stuart, you are a new diver, there is still a lot you don't know.
True! But, I did know that. And I also saw that the OP already did classroom (I'm assuming they did classroom before confined water) and at least one confined water session for OW. So, the normal combined OW+Dry Suit option is out unless she/they start completely over. I think she/they would most likely have to start the dry suit course separately and do the pool for that before going to the quarry, and then get all the OW dives combined.