What airframe/engine combination do you have?
This AAN:
http://www.caa.co.uk/aandocsindex/27632/27632000000.pdf
Validates STC:
SA00079NY. If your bomber is in the AML for this STC then crack on.
If not search the CAA AAN database for all (previous to EASA bollox) validated STC's. There are loads for Airwolk and B&C.