I don't think that's quite what the OP is after.
As I read it, he wants to run two US (110v) devices, each with its own US-style 2- or-3-pin plug, from a 240->110v converter which only has a single socket. So he wants a single->double US socket converter.
If he wants to be drastic, he could cut the plugs off the devices and replace them with UK-type ones, then use a single adaptor, but it's not really a good idea to put 240v-type plugs onto 110v equipment.
On the other hand, Amazon do a step-down transformer for about £17. That's probably the cheapest option.