I live in the Uk and have been doing judo for about 3 years now (I'm also 32) and I absolutely love it.
There are not a huge amount of competitions for adults below black belt standard but they seem to have about 2 a year where I live (south coast). You can compete in these competitions as a white belt as they are normally graded so you would only be fighting other white belts.
I think judo is probably the best grappling art for self defence due to the high impact throws. As they say, if MMA was done on concrete floors everyone would do judo.
Can I ask where you have been doing wrestling? I'd love to try it but there are no schools anywhere near me.
I did my wrestling in South Africa, when I was in school. But you're right, the are not many wrestling clubs around in the UK.
What grade are you? And would it be too adventurous of me to set a goal of getting a brown belt by the end of 2013?