On the back of the programmer, switch 5 should be in the 'down' position.
That is all you need to change.
I just changed this, the boiler still does not come on when I tell the heating to fire up on the controller.
Did you press Reset after changing the switch?
Ok I did this. This only allows hot water and heating to be on the same timer. Ie one cannot come on without the other. Is this all we have on this system?