[frauke]

I presume you have already been to the event.

But I will mention, for the travel costs - if you are using your personal car. Rather than keep the petrol receipts, and just claim those - you can make a "mileage claim". The first 10,000 business miles you do in any tax year you can claim 40p a mile, and 25p a mile thereafter. Its a lot simpler, easier - and helps to provides additional justification of the overal claim, as you have to record the details (miles done, to where & why) to claim the 40p a mile.