Fillet of beef help!

[cashmerecardigans]

I'm cooking Jamie Oliver fillet of beef, but my fillet is half the size of the recipe.
Any ideas how much I should reduce cooking time by? It says 35 mins for medium rare for a 1kg fillet, mine is only about 500g.
Any thoughts much appreciated, can't afford to mess this one up!

I'd go for half the time and see how it is then.

I use this calculator www.cookingtimes.co.uk/meat/beef

Fab thanks, @Unescorted done the meat calculator and it equates to about half, which makes sense and is what @OrangeBlossom28 suggested
Thanks so much, panic (and overcooked beef) averted

Enjoy your beef!

Thank you, will do! Just need to ensure my fizz drinking doesn't derail me