I swear I read somewhere that Thomson were also adding San Jose, Costa Rica to the already announced flights to Liberia, Costa Rica but after searching online it appears that Thomson Holidays are indeed offering San Jose as a destination but using BA as their flight option so it does appear so that Thomson won't be operating their own flights to the capital of Costa Rica only to Liberia.
I did wonder at the time if it was a bit of an over kill for Thomson to have two destinations in Costa Rica.
On a personal note having been to Costa Rica myself I do recommend it as it is a beautiful country with so much to offer.