Why don't you disconnect the current one completely then install new one.......then try and reconnect old model after that 
That's best I think. Had enough disasters for one week.
I'll 'ave a brew and another snout, and then do the BIG plug in while I've got the place to meself.
managed to finally get BBC 1 NW on the other one btw, but all NW channels are now in the 8 hundreds!

I suppose this will be the same until they turn the bloody turbo signal booster up at Winter Hill, gormless useless eejits.