Given the following context:

During the Second World War, people converge on the Halfway House, an inn in the Welsh countryside. In Cardiff, the famous orchestra conductor David Davies is advised by his doctor to cancel a tour and rest, or he will live for only about three months. In London, Richard and Jill French argue about the education of their young daughter Joanna, who overhears them agree to divorce. Then Mr. French and Joanna go on vacation. Captain Fortescue is released from Parkmoor Prison; he was court-martialled for stealing the regimental funds. In a Welsh port, merchant captain Harry Meadows and his French wife Alice quarrel about their deceased son, a victim of the U-boats. Black marketeer Oakley departs from London for some fishing, while Margaret and her Irish diplomat fiancé Terence take a train from Bristol.
Oakley and Fortescue meet on the road; it turns out they know each other. Though Fortescue had scanned the countryside thoroughly with his binoculars in vain for the Halfway House, it mysteriously appears. When they reach it, the proprietor Rhys also seems to materialise out of thin air. He tells a puzzled Fortescue he was expected. When Oakley signs the register, he notices a long gap after the last signature, dated 1942, it being 21 June 1943. (The newspapers are a year old.) 
Others arrive; the Meadows request separate rooms. Rhys serves a grieving Alice tea in her room. She is shocked to see no reflection of Rhys in the mirror when he leaves. Mr. French notices his wife's handwriting in the register and suspects that Joanna arranged for them to stay in the same place. Later, Fortescue is sitting outside when he notices that Gwyneth, Rhys's daughter, casts no shadow, though Joanna, standing nearby, does. Joanna arranges a fake near-drowning, with the help of Captain Meadows, to try to reunite her parents; it nearly goes awry. Margaret and Terence quarrel when he is eager to accept a posting in Berlin (Ireland being neutral).

answer the following question:

What is the full name of the character who appears to have written in the register to the surprise of their spouse? 

Jill French