Great beginning -- drew me in. This is a book I would buy.
Where I needed a bit more convincing was Neil agreeing to do what Caro wanted. I’d like Caro to have something she threatens him with (we don’t even need to know what it is at this stage) to make him submit.
Neil is a great balance between loser and special – as a reader I can anticipate tensions and problems.
Caro – not so much. Hints that she could be nasty in the past (cigarette burn), but she’s almost too ‘normal’ now. I think you could come up with something more unique and twisty for her (all her time off/money is spent throwing dummies out of hotel windows! I’m not entirely serious, but maybe you get what I mean).
My reader's heart sank when I realized I was going to have to sit through the whole journey to their old hometown. I assumed we'd either jump to their arrival at the hotel where Davey was murdered, or be diverted onto a completely unexpected (but wild and interesting) subplot to delay our arrival at that point.
Of course, with a murder mystery, you are dropping in plot clues that the reader doesn’t see the significance of at this time, so it may be that some of that conversation has to stay, but perhaps it could take place in the hotel lift? so that the reader knows to ‘hang on in there’ ghostly happenings are imminent.
I hope these comments are relevant/useful - this is the style of story I love to read.