Hey Fran congrats on your win and glad to see you enjoyed the show ring I had the exact same problem with Ruger when i first showed as had not intended on showing at first and of course the first thing she learnt was to sit and of course did this in the ring the first time but had great experience similar to yours so still had a great day. I have heard of lots of people not teaching their dogs to sit cuz they show them but i still think sit is a very important command. As with what others have said i practiced a couple of minutes each day with her and yes she was doing the same as Luuka but i would just put my hand under her belly and keep it from going down and she caught on real quick. Once i was happy with how she mastered stand i then moved on to having her stand and let me move her feet into the correct position. She can now be told to sit stand sit stand and will do these commands...just took a lot of patience and time and now in the ring she can stack herself about 80% of the time with me not even touching her. thought i would share this as i know you know of Ruger hehhe
Good luck with the shows and keep practicing