@helenclayton The only bottle solution I have had working even remotely are these drippers with regulators on them. Funny enough I looked up these in the UK just this weekend because a friend had exactly the same q as you, going away for two weeks.
https://www.webbsdirect.co.uk/garland-adjustable-little-drippas-set-of-4/

@helenclayton I have tried several varieties of this and gave up. My greenhouse is now watered by a solar powered micro drip system and it works wonders. Relatively cheap (off-brand), reliable and works do well i had to push tomatoes on my neighbors last year, from four plants...