Suggested by Dave Casson this area allows us to share info on suppliers and parts send me any info you have via the Contact Me page
Most masts by Z spars UK
Mast head sheeve, try part no. 1616 which is 45 diameter 13 wide 8mm pin diameter made from Delrin
The vast majority of springs are fitted with a Yanmar 1GM10 a trusty single cylinder diesel.
Try Marine Power for the South Coast, great on knowlege and advice
Oil Filter try one of these from a motor factors for a direct replacement for teh Yanmar part- MAN W811/80, Coopers 2819, Mazda323 or Crosslands 672 ( I use the MAN so can't vouch for the others)