I did indeed - it was registered on the V5C as Dual Fuel as well but despite my protest that it burns cleaner and LPG was (at the time) exempt - because it was 'originally' a petrol powered gas guzzler I had to pay the charge.
I also had an issue with a 200tdi powered Ninety - the DfT ULEZ online vehicle checker said it was exempt from the ULEZ charge so I drove it for two weeks into work which was half a mile into the zone - I got a letter saying if I was to do it again I would be fined and taken to court for failure to comply....I took a screenshot of the website page that told me that my vehicle was listed as exempt according to THEIR website....I was told, again in writing, that the checker was for guidance only, and the I should know that my Ninety was an almost 30 year old diesel pickup and that it would be subject to the charge regardless of what their online vehicle checker said!
I wrote back protesting the fine on the basis that I do indeed know what my vehicle was, but thought it best to check with THEIR online checker in any case and I was pleasantly surprised that it said it was exempt - thinking there might have been a loophole that my Ninety fitted into - so I drove into the zone thinking I was complying.....they wrote back and basically told me there was an error on the system and that my vehicle was indeed subject to the charge and if I continue to drive into the zone without paying I would be taken to court...I spoke to a solicitor and he sided with them and said 'Come on mate - its a 1988 Ninety converted to run a 200tdi, its a pick up and is classed as a light utility vehicle an by that definition alone it is subject to the charge regardless of what their online checker says....by the vehicle description I must have known it would not be exempt....he did argue that if they tried to charge you for the back dated fines, I might have a case to dismiss those, but continuing to violate the zone rules even after they have warned me twice not to do so.....they would win any case I bring to them.
Needless to say I was non-plussed, but complied in the end and didn't drive that Ninety back to work anymore!