When you say you want to take your snake for a "checkup," is there a specific problem you want looked at? If all is well with the animal, there is nothing that such a checkup will tell you. Unlike dogs & cats which have their annual shots and a general health check at the same time, a vet will simply look at all the signs you, yourself, recognise as normal - alertness, tongue-flicking, skin condition and general demeanor, tell you that all is well, and relieve you of a big sum of money. You may well be exposing your animal to infection from other snakes previously at that vet. Unless there is a specific problem, such a checkup is pointless, other than to relieve your anxiety. Without symptoms of any kind, the visit will tell you nothing.
I certainly don't mean to be critical of reptile vets in any way, and I can say from personal experience in the past with both Tims at Wattle Grove, that they are excellent practitioners. (I sold Tim Hyndman his first snakes when I was a dealer in Perth, before he went on to Murdoch and further research - he's a delightful and very agreeable young man!).
It's obviously your choice, but it's worth giving some consideration to the points I've made above. If you know any well experienced keepers, you'd probably be better advised just to get one of those to run their eyes over your animal if you're anxious about its health.
Jamie