Just got back - had a great time. Thanks for all the good advice; we visited Lake Bled and Ljubjana in great weather - lovely places, lovely people.
We also ventured into Croatia for a short while. No problems at all. No queues at the border and they didn't even bother to look at our passports going in or out.
Its only coming into or out of Britain that border controls really step in - we had an inspection of the m'home going both in and out; fortunately nothing heavy on either occasion.