can anyone give me some advice of how much is a reasonable price to pay for a labrador puppy?  I have seen them range from £350 upto £600 is this normal?  The £350 is in wales whereas the £600 is in the south east.  is it just a regional thing?   Should I steer clear of cheaper ones for any particular reasons.

Check if both breeders are members of a breed club, that they carry out the essential health checks in their breed, are the parents hip scored and eye tested?

How many litters has the bitch had, how old is it, all these questions will steer you to a responsible, ethical breeder.  Price does not always reflect quality.  And of course there are regional variations.

Remember cheaper in the short run can mean more expensive in the long run if you buy from unhealthy/unsound stock.