In reply to tnj:
Thanks for the advice everyone. I think I can convert them using the method suggested by Edvin M. At the moment the points are mounted outside the frame and so the spacer inside is actually too large if a single point were to be mounted inside the frame. So I think all I need to do is remove the correct amount of Spacer to allow a single point to be mounted and I can use them with monopoints.
Out of interest, has anyone else found it difficult to get the secondary points in contact with the ice? SOme reviews have suggeted this,but said they are very good for mixed. So maybe that is how I will use them.
Cheers
Tom