I tried to look up that kit, but having some difficulty . . .
The designation TY-FP12 would suggest Tyzack Tools, but I can't find pen kits on their website.
( I did find the kit for sale at Turners Warehouse, but that's on this side of the Atlantic and obviously you'd wanna buy from your side. )
Would you please give a link for where you bought . . . I am just checking things out at the present time in an effort to provide some help
in finding a vendor for the bushings you need.