All finished (and with 2 days still before the formal!). I undid the waistband and trimmed the netting only. This left the lining and bias strip allowances as buffers against the bits of net left. After a quick wearing test I stitched the binding back on.
The picture on the right is one shoe before the make over and one after. I just put a ribbon on the shoe, tied a bow and attached a heart shaped bit of bling I got last time I was in Hong Kong. I think they were something like 10 cents, so if they don't last the night, no matter.