We have designed a new cleat base to convert Spinlock to Harken for those that prefer that method.
Due to the width of the base of the cleat frame we previously extended the Harken cleat backwards, which some people were finding too close to the gennaker bag. By inverting the bolts and countersinking the plate you can now retrofit the plate and place the cleat in a more forward position. Available in either plate only format (for £21 plus VAT and postage) or complete with cleat, fairlead and bolts (for £60 plus VAT and postage).
Plate only viewed from below