My application is slightly different to one where a suppression device is fitted across the relay coil and switch contacts, as I don't have access to either of these my X2 cap' is directly across the whole ring main and as close as possible, adjacent 13A socket, to the surround sound system, the 10nF works in this position and from the Farnell sheet posted it gives me an idea of what resistors are used in commercial components.
When my new X2 caps arrive I'll try with various resistor values as although it works fine as it is, with a resistor it should reduce this inrush current.
Thanks
John