If they live overseas, you may be better off buying through Amazon and letting Amazon deliver, as the postage costs could be quite high.
I would 100% recommend ELC's Happyland things though. DS has loved them, and he still plays with them now and he's 4 and a bit. Mothercare is doing 50% off a lot of it and 20% off some of it too. That would be fantastic for the 1 year old. Or some megablocks. Or an aquadoodle. Or some 2 piece jogsaws (something to grow into over the next year).
For the 3 yo boy, I would recommend a Bosch toolbox, doctor's kit, very basic camera (not a digital one, just a play one), Fisher Price Imaginext range of toys (the helicopter and submarine are both really nice), torch, play shopping things like a till and baskets and play food and play money, anything at all dinosaur or train related, magnetic board with magnetic numbers and letters ...
For the newborn baby, I would recommend a whoozit spiral toy, or a highcahir toy (basically a toy which has suctions at the bottom so that it stays put on the highchair tray) a grobag/sleeping bag.
For toys, I don't think you can go far wrong if you buy from the Melissa & Doug range, as the quality is fantastic and they have some brilliant ideas.