Further update on the problem. Having tried turning the SH2 off and then on again as well as pressing the reset button still we were without a phone line. However, on yet another conversation with a BT representative they happened to mention their system showed we had not been online for something like 5 weeks. They was it........that was when we plugged in the brand new router, the only thing being we had been online everyday since then, very strange. Eureka, the penny dropped and the thought emerged our brand new router was actually faulty. Suffice to say another brand new router gets plugged in and everything works fine.....fingers crossed.
So, don't assume that a brand new 'out the box router' is 100% perfect.