I have no knowledge of George (an uncommon Manx Name)
Sir Crellin is I strongly suspect a misread - however there are no Crellins in Cronkbreck pre 1607

Cronkbreck(or Knockbreck or similar breck/breack etc) is a qtrland in the treen of Alia Kneebe rent 16s pre 1704 + 32s after 1704
a Thomas Crellin purchased it in 1607
the sequence then runs Philip then Richard then John then Philip then John then John (not bothered after this as you are now in mid 18th Cent and wills/burial reg etc will help)
there are entries in lib vas where rge treen + chief rent are easily spotted, 2 (maybe more) marr contracts