this is from the food standards agency - it is perfectly ok to defrost and cook raw meat and then refreeze it:
Freezing meat
It's OK to freeze raw meat providing you do the following things:
1)freeze it before the ?use by? date
follow any freezing or thawing instructions on the label
2)defrost it in a microwave if you intend to cook it as soon as it?s defrosted, otherwise thaw it in the fridge so that it doesn?t get too warm
try to use the meat within two days of defrosting ? it will go off in the same way as fresh meat
3)cook food until it?s piping hot all the way through
When meat thaws, lots of liquid can come out of it. This liquid will spread bacteria to any food, plates or surfaces that it touches. Keep the meat in a sealed container at the bottom of the fridge, so that it can?t touch or drip onto other foods.
Always thoroughly clean plates, utensils, surfaces and hands after they have touched raw or thawing meat, to stop bacteria from spreading.
If you defrost raw meat and then cook it thoroughly, you can freeze it again, but remember never reheat foods more than once.