Two thoughts...

1) The FRA stop is your destination, not an open jaw. Doesn't really matter, but if you had chosen to take the train from Frankfurt to Munich and fly MUC-LHR-IAH then you'd have FRA/MUC as the open jaw. In this case you do not have one.

2) In London we stayed at THE MAD HATTER HOTEL. We liked the location and there were some good restaurants not far away. The hotel was just OK but also priced that way.