My wife and I visited the three Montessori Nurseries in and around Glasgow - Yorkhill, West End Montessori, and in Killearn.
We were most impressed by the nursery in Killearn. The manager had a lot of time for us, showed us everything, and radiated a real interest in and care for children. The garden and outhouse are wonderful. Everything about the nursery said "nurturing". Sadly, it was just too far for us to travel (45 minutes to get there).
The West End Montessori came second in the impression-stakes. The owner was very enthusiastic and was genuinely friendly towards our daughter. She said that there would be definitely be a place for our daughter within two months of our visit. Four or five months later we were still waiting and the secretary, while very friendly, could not give us any indication of when our daughter could start. With some regret we gave up.
The Yorkhill Montessori, while owned by the same woman who owns the Killearn Montessori, had a very different feel from Killearn: noisy and somewhat jarring. We had decided to send our daughter there and the manager asked for a £100 deposit, which was the first time we had been asked for money.
Eventually, we decided to send our daughter to a nursery in Lenzie, which while not a Montessori is very good indeed.
Good luck with your decision!