Why would you want to rewire the lights just because they are in singles? I meant to say there is no correct way to wire lights :) There was a t that should not have been there on my last post.
There is nothing wrong with singles. If all your switches and fittings are earthed and the cable is in good order then you would be rewiring for nothing. The switches will take 3 cables per connection and you can easily get 4 earths into a back box earthing terminal.
Adam