Yes they are, there's a decent FAQ on their website which explains exactly what they do and how they do it, the warranty you get and anything else you might want to know. I emailed them with a few more questions of my own and had a very quick response which put my mind at rest.
I read plenty of reviews on forums (including this one) and it all checked out so I placed the order. Other than it taking 7 days instead of next day as you might get with a UK company, the eperience was identical in terms of confirmation & tracking emails etc. I saved over £1k on the lens and it arrived via DHL very well packaged in all original Canon boxes etc. exactly as if I'd bought from Wex, London Camera Exchange or anywhere else in the UK.
