Andrew Wiles wrote:
Thanks Adrian

This looks like the answer. I am assuming that the Application.Volatile
reference is switching this feature on for ALL udf's and can therefore be
placed in any startup code for the app.

You'll have to test to verify it, but i don't think it's a global
application setting - at least what's mentioned in Excel's help file,
the setting goes inside the start of EACH UDF that requires notification
of sheet updates.

Looking through some of the other posts relating to application.volatile it
appears that for Excel Services this can be declared using reflection for an
individual function. Are you aware of whether this technique could be used as
part of an automation add-in for use inside a normal Excel session?

Depends on what the user is running in the 'normal Excel session'. If
he/she is running other data driven or calculated stuff, something like
Application.CalculateFull could be harmful if done at the wrong moment!

Instead of getting the cells to pull data from UDFs, can you just write
/ paste the data in from your remote service?

--
Adrian C