I've got my problem sorted now thanks.

If I've understood what I have read on the other threads concerning problems with BT pan and some Sony Ericsson phones (incapable of connecting via GPRS?), then the Pan 1.0.1 is essential if you have the latest up to date Diablo as this provides you with a DUMMY connection if you want a internet connection through these phones.

Before I upgraded to Diablo I did not need a DUMMY connection to connect via BT Pan on my phone, previously I had connected to 'Bluetooth-Pan'

My problem since downloading Diablo/BT Pan was that the DUMMY connection was listed at 'Connectivity Settings' > Connections > but the DUMMY connection was not available to select in the 'Select Connection' box making it impossible for the tablet to connect to Pan.

(click wireless icon to view all these options)

I'd suggest anyone else having this problem tries rebooting a couple of times after installing as thats eventually all I did - now I have an DUMMY connection listed next to my wireless access point in 'select connections'

Thanks to all who have helped.

Must either be symbian based ones or phones with custom operator firmware, as i have never had a problem using my two latest SE phones using either BT-DUN or BT_PAN...

It's a SE badged as Vodafone if that helps?

Then i would say its very probable. Not that i am personally familiar with vodafone branded products, but i have the impression its not one of the brands that do the least amount of firmware fiddling...