Good suggestions
Id also present a letter by you as the spouse saying you financially support her during trip.
BUT most important give supporting evidence that she is going to return to Thailand. While having property is one, it's not a strong one, A job in Thailand is a good one or family in Thailand (another albeit on the weak side)
Another word of caution. VFS is brutal to deal with! They have no problem rejecting applications for any reason. And since they answer to no one they don't care (they are not the UK government they are just an agent). So make sure everything is don't 100% correct. They don't care if you leaving in June. They only care about themselves!!!
Overall. Tourists visa for. Spouse is not that hard or difficult. And usually approved. Just make sure application is filled out in full and correctly.
Good luck