Thinking about moving my QC PSU and needed a longer lead so rather than faff about I thought the easy way was to make an extension lead. A quick search on the web suggested the plug was a Bulgin SA2403 I ordered a SA2403 and SA2404 from CPC but when they arrived they clearly werent the right things.

Disconnecting the lead and looking at the miniscule part number it is a Belling Lee L1436/P !!

ordered from ebay now, hope the heads up helps someone sometime