Topaz underslung LPG tank

As any Topaz owner had LPG tank fitted any observations would be welcome,thank you

I've no direct experience, but the problem you are likely to face is the presence of the water tanks, as these take up the space where a tank would normally be fitted on a T5 (though I understand that a 2005 van ~might~ be T4 based).

Speak to Chris Wise at Autogas2000 - at Carlton Miniott, near Thirsk.  [You must be registered and logged in to see this link.]

He may know, plus he's a very helpful and thoroughly good bloke, so I'm sure he will help if he can.