Paul,

Thanks for your rapid reply.

Yes, it is logical that a calling button cannot delete itself.

Sometimes in life one needs someone to give a flash a the blindingly obvious; you did that to me, thanks.

There is no reason why the user needs to see a form with which they are already (or soon will be) familiar.

Now, the form opens up on opening the doc and everything is right with the world.

All the best,
Simon