Thanks for the quick reply, yes indeed it was. As mentioned I upgraded both MSN and MsgPlus today and just assumed it was MsgPlus causing the problem. I didn't see that option in MSN as it signs in automatically. I closed it and opened it manually just now to check the settings.
Apologies to Patchou for thinking it was MsgPlus and thankyou again for the reply. It seems MSN sets itself that as default when re-installing/updating