Hi here's my 2C.
First off, I think many of the local kids are kept up much later in the evenings than we in the UK would be used to - I think primarily because parents tend to work long hours and so the evenings are family time. I often see very young kids up and out for dinner as late as 10 in the evening - I know mine are always tucked up in bed and asleep at around 7.30pm so would not need a long nap in the daytime.
In terms of your options, it really depends what you are looking for. Given that you want somewhere you can drop him off and leave him for a few hours presumably you want more than just a playgroup type of thing. There are a vast number of kindergartens/pre-schools/childcare centres around. Just take a look in Yellow Pages! Bear in mind that the climate here means a lot of the activities are indoors although many places do have outdoor playgrounds the kids don't seem to use them much. These type of childcare places are geared (in my opinion) towards local kids and tend to focus on things like learning ABC's, practising numbers, doing colouring in etc. Many describe themselves as Montessori but they are not what I would call "proper" Montessori, they just use Montessort materials or have a half hour of Montessori a day. I would say they vary in quality but your best bet is to go and see a few near where you live and just see how you feel. Then there are others which are more popular with Expats such as White Lodge, Pibo's Playhouse and others - best option is just to turn up and see if you can have a look around, then you will get a feel for how friendly they are, what the mix of kids is, and what the kids are doing and what the routines are. For example some of them give the kids showers and put them down for a nap but there is no way on earth I would want a stranger giving my kid a shower!
Another option would be something like Julia Gabriel where there is more emphasis on creativity, music, art and so on but am not sure if they can go unattended at this age.
A third option would be a nursery class at one of the
International Schools such as the German European school, or somewhere like Eton House or Chatsworth, which is more expensive option and a bit more like "real" school although there would be more emphasis on play. Typically they use expatriate teachers who have trained or worked in Europe or Australia so might be more in tune with UK attitudes. They usually take kids unattended from 2 years.
Hope that helps