Kozap do one for the 527, for the 452 look here.
J&P Custom Products, LLC
Make sure you know what size your 452 dovetail is, either 3/8" or 11mm, 11mm measures 11mm across the top of the
dovetail, the 3/8" measures about 12.7 in the same place.
You could also get a full length 452 rail from
Diversified Innovative Products - Product Detail - 452/453 3/8" Picatinny Scope Mount - $42.97
For the DIP rail you could try contaction HotRod 9mm on rimfire central forum, sometimes easier for shipping to the uk
as he actually makes them.
Neil.