Just get a generic box (non-Sky) and take a feed off the LNB on that. Point the dish towards Hotbird or Astra 1 etc, and retune the box for channels, and off you go.
The only problem is, as a lot of the foreign services use satellites that dont have a strong footprint over the UK, you may well need a bigger dish, as the dishes on Sky are not big enough. This will also mean a new LNB, as the ones on Sky are made to work with the shape of the minidish.
You can actually pick the boxes, dishes and LNB's up from the likes of LIDL and Aldi nowadays, although they are promotions only. Best place would be Maplin. You can get some stuff with Sky Digital boxes, although you can't add it to the EPG.
Im pretty sure that only Sky broadcasts off the Astra 2/Eurobird sats nowadays, which is at 28.2 degrees, so you would deffo need to be interested in re-aligning the dish etc...
Question is, is it worth the hassle lol.