pedestal basin

I have a cracked 600mm 2 tap hole pedestal basin made by shires - no longer available) which needs replacing. Can I put a new basin on top of the existing pedestal?

Switched out pedestal basins for vanity units earlier this week, but the pedestal has left a huge hole in the pipe boxing underneath. What do you think is the best way of patching up these holes? They're hidden away so I'm not worried about retiling, but I feel like there has to be a better...