You are right to be concerned!
Persimmon have
never been rated 5 star by their customers in the HBF survey. (4 stars again this year!)
Persimmon won just 13 NHBC Quality Awards in 2013 (Barratt won 102!)
My advice would be not to have anything to do with Persimmon aka Charles Church, [and Taylor Wimpey!]
Read the posts on here and at
http://forum.snagging.org/persimmon-homes/If you still go ahead and buy regardless, then you will only have yourself to blame!
If you do buy any new home, be sure to have it professionally inspected and snagged BEFORE you legally complete and move in.