Truma water heater ventilation cover how is it removed

[twokcc]

Always run water heater on 240v but going on CL later this year and will have to run on gas. Anyone any idea how o remove vnt cover, manual says just remove it with no indication how.
Found this removal tool

https://www.caravanparts.co.uk/product_popup.php?p...

do I need one of these(doesn't say I do in maual) or anyone know a way of removing without tool.
Caravan is a 2009 Swift

[twokcc]

Thanks for reply folks, tug wouldn't budge it so used car trim plastic removal tools and it popped off.
Thought I'd broke it a thin piece of plastic fell out-but different colour and not from cover or part of vent.
Looks as if previous owner devised his own anti theft/loss solution by using the piece of plastic at bottom of cover which makes it almost impossible to lift up and over top lugs.Refit without piece plastic cover goes on/off easy as you advised.