I booked a Nairobi – Amsterdam – London flight with a European carrier. This was booked under one booking, made under one transaction, with one reference number.

The first flight (Nairobi – Amsterdam) was fine. However, my Amsterdam – London flight was cancelled, and I was provided with a later flight that got me to my final destination, with a ten hour delay.

Under EC 261/2004, should I be eligible for:

 - compensation accounting for the whole journey (over 3500km) which
   entitles me to a compensation of 600 EUR, or 
 - compensation accounting for only the Amsterdam – London flight
   (<1500km), which entitles me to compensation of EUR 250?

I would be grateful for any advice, or recent, relevant cases – I have seen some similar questions here but none that are precisely equivalent. The airline has stated that as the disrupted leg was the Amsterdam – London, I am only entitled to the EUR 250, which I would like to challenge.

Many thanks.