Cellini, have you contacted Greyhound Rescue West of England, or South West Sighthounds?
You could also get very quick specialist help if you post on Sighthounds Online forum - there is a dedicated section there for dogs needing homes.
I think it would also be fair if you indicated that you were willing to pay for food, but also for vets bills/insurance etc, plus a foster allowance. It also helps if you give a clearer indication of the likely timescale/microchip issues/what happens if things go wrong and so on.
It might also be worth trying Cinnamon Trust as they are based in Cornwall, but to be honest, I am reluctant to recommend a lot of the usual charities as they are mostly bursting with emergency cases.
As your dogs are so good with kids and so on, you could also consider placing an advert either in your local press, local shops (esp animal feed shops) or your local mums/toddlers groups.
Sadly this is a very common reason for dogs to be up for rehoming with charities, but illustrates perfectly that rescue dogs are often given up reluctantly and are "tested" with kids and usually wonderful family pets.
Cellini, what is your timescale? Also helpful for rescue cases - need to know how quickly the dogs will be homeless. Finally, what is the age of the dogs?