OK pick up the prescription tomorrow!
Now did you look at that cruise? I know you probably don't like the sound of them (thinking they're for older people, etc) but these are my reasons!
You can sail from a UK port - just drive down to Dover or wherever and get on the ship there
You won't have to cook anything for the length of time you're on it
You won't have to do any housework
There are babysitters on board
There are children's clubs so the kids will be happy
You will have a lot of time to yourself
You don't have to do any of that dressing up for the captain nonsense - they always have buffets you can go to where you don't have to dress up
You can sit out on deck in the evening with a gin and tonic in your hand and your notebook and you can make plans for your next novel!
Seriously consider this. With any other holiday you will have to compromise, eg on travelling, cooking, cleaning, babysitting, children's clubs etc.