Turkey - Fan Oven or 'Regular' Oven?

According to teh directions our turkey (just a crown) needs about 4 hours to cook fully.

But I'm wondering, should I put it in the fan oven or the regular one?

Help!

4 hours!  How much does it weigh? I cooked a 7.5 kilo whole turkey in around 3 hours. I never use the fan when I cook my turkey and always follow Nigella's cook times. Not sure if it's too late for this, but I highly recommend cooking it from room temperature.

At least you have a choice... mine's fan or nothing!

At least you have a choice... mine's fan or nothing!

Ugh! I only use my fan when I am making cakes or I'm doing oven fries and feeling very impatient. 

4 hours!  How much does it weigh? I cooked a 7.5 kilo whole turkey in around 3 hours. I never use the fan when I cook my turkey and always follow Nigella's cook times. Not sure if it's too late for this, but I highly recommend cooking it from room temperature.

It weighs 2.5 kilos.

The instructions said it needs 50 mins./450g so I was thinking it needs about 4 hours.

We're doing ours in the fan oven. But it's 8.2kg. 

I'm curious how it turned out.  We did a turkey crown in about an hour, but it was probably smaller than that.  Four hours still seems mad for a crown though.