The first rejection due to not following the rules, stay in Vietnam while processed, may have caused them to reject again. It could be seen by the assessor that you do not follow the rules of the visa.
Pure Language courses are not usually approved. There are some that include some cultural activities too that are. As the other poster says, change the SP.
The reason is these type of stories just give fuel to the fire for those that want to cut benefits and make it harder for people to claim. Stories like this are red meat to The Sun, The Mail and The Express never mind certain parties of the right. I am quite a lefty socially (ex miner, politics and economic history grad) paradise but even I can see how this looks. "Unfit to work but fit enough to galavant in a tropical paradise" would be the headline.
Let's pay everyone to come on holidays as they are not using the NHS while away. Good one. She also has a Work Coach, which I assume it is try and get her into some sort of work for which she is able.