Although both Mouser and Digikey do now advertise direct to the UK, you need to be very careful that you don't get stung with excessive shipping charges, Customs duties, and fees.

I was obviously not careful enough, and ended up paying vastly over the odds through Digikey due to shipping charges, Customs duties, and fees - which also delayed the delivery.

:-(

Again, speak to your Tutor first to check if there are any arrangements in place for ordering via the University...