Heheh, coincidentally, I was discussing these in another thread.
I am not entirely sure how difficult or easy ordering from this American company would be for you, but I bought this one to clean my airbrush:
http://www.harborfreight.com/ultrasonic-cleaner-3305.html
Stuff I like:
The removable basket.
The price.
It works well!
Stuff I don't like:
The unchangeable and short cleaning cycle.
For you, the small size will be a concern.
People who needed larger and more flexible timer settings got this one:
http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html
Quality from Harbor Freight can be more miss than hit at times, but my little ultrasonic has been going strong. I cannot personally vouch for the quality of this larger one, but both of these can be had for 20% off with the ever-current coupons on the store's site.
For cleaning paint off models, though, I've never bothered with a sonic cleaner. I use Purple Power ( someone will hopefully chime in with the name of the European equivalent cleaner) and one of these:
http://www.amazon.com/Rubbermaid-1839685-Reveal-Power-Scrubber/dp/B00BEUDWJQ/ref=cm_cr_pr_product_top
That's not Gary Busey's electric toothbrush- that's the Reveal Power Scrubber. It's brush spins significantly fast, and I have never seen a paint job it couldn't strip as long as the model spent some time soaking in Purple Power.
Power Scrubber Pro Tip: use in the shower or outside if you don't want your sink area looking like a Jackson Pollack piece after stripping a few models.