Bluetooth for E6430 Short Range Only - and Distorted

I have just retrofitted a "375" Bluetooth module into my Latitude E6430 running Win 7 64 bits. The card I am using is actually from an E6420 but I'm pretty confident the 375 (BT ver 3.0) will work in my 6430 - although the 6430 normally uses the 380 (ie. BT ver 4.0) module.

The card installed easily and correctly and after finding a good driver from Broadcom using their driver utility I can see the Bluetooth Radio in Device Manager which says the device is working properly.

I can also see the BT icon in the tray and I can find BT devices... It connects Ok to my Logitech BT audio device and I can stream music to my stereo this way and the music plays fine, except the range is only 6-8 feet and in fact if I'm sitting in front of the notebook and/or put my hand over the keyboard the music becomes distorted - cuts in and out, scratchy, skipping...

The 375 BT card i'm using worked perfectly in the 6420 I took it out of so i don't think it is a problem with the card...

So am looking for ideas and advice on why it's behaving this way and what i can do to fix it...

Thanks and regards.