Where did you find the spurious ones?I got a spurious set off ebay last time. Had to take a hair off the hole to get them to swing freely. This was for a 10ft, belt driven. Rightly or wrongly, put longer ones on the centre to delay the stripping when they wore. ~£20 apiece.
I looked for similar last year and got the £40 surprise so made do. Will need something this year. How do you spend £250 on a topper that's probably not worth much more than a grand?