Just told him I've noticed significent drop in signal from Sensation, lots more T-Mobile log ons too. He quite quickly said get fone swapped.
Orange reply as above, blaming local masts.
The signal seems to jump from one extreme to another either full bars or one bar only.
I can have my phone on the desk and I am actually seeing the wifi strength and the mobile signal fluctuate between 0 and 2 bars. It does that most times I take it out of sleep mode, it does this for about 60 seconds then stabilises. Happens almost every time.