WebPlus X6: Delete my old sites now I have a new one?

Hi there,

I've just finished constructing a singe site that has replaced 3 separate sites.

I've set up redirectes from all of the original pages to go to the apropriate new pages. Can I now completely delete the old sites or should I leave them 'active'?

I would like take advantage of the previous ranking.

Is there anything else I should consider?

Many thanks
Steve