Hi Gail
I can't tell you whether or not you should challenge something - everyone has to decide for themselves.
When I first read your post, I thought you had lost your award, but reading it a second time - it's the letter you lost and therefore you have been given an indefinite enhanced award for both. Why would you challenge this? You couldn't have got a better outcome.
If you ask them to look at your award because you scored zero points for planning a journey - you run the risk of them looking at your award again and possibly changing it. It may be a small risk, but it is a risk. If you feel strongly about it - you could write and say that you are satisfied with the award but are disappointed that you scored 0 for planning a journey and would like your comment added to your file. You can't be awarded anything better and I think it is unlikely they will change it.
However, the choice is yours.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems