New childcare tax free scheme

[Limpetsmum]

Am I right in thinking come autumn I'm going to save a fortune in Childcare. Currently have a nanny for three kids (4 days a week) + one day nursery.
I pay £2000 per child nursery x2 = £4000 (one child gets free 15 hours) +
Nanny = £20,000/year for four days a week.
Total = 24000

Does that mean I'll get £4800 (20% of 24000) from government?

Currently all I get is about £900/year from Childcare voucher scheme. It seems too good to be true.

Just want to check that scheme covers nanny pay and not just for nurseries.

I dont know exactly what is the expiration date of the childcare vouchers but you dont have to use them as soon as you buy them.

A simple 20% of all registered childcare with a cap for people earning mega bucks would have been nice & simple.
Why do they have to make it complicated?

Can I use the new scheme if DH remains on the old scheme? (am self-employed so don't qualify for old scheme).