Advise needed on fitting new vent/cutting roof

[MattBW]

The previous owner of my van, replaced the leaky leisuredrive skylight/vent with a piece of perspex, wooden beading and copious amounts of sealant rather than fork out for a proper vent. After struggling I have finally got it all out, all bar the perspex to keep it weatherproof. Leisuredrive simply didn't respond to any requests for replacement vents or what the standard size was so I had to make a best guess and buy aftermarket.

Once I cleared all the crap, the vent hole is slightly smaller than the skylight and I need to cut the hole slightly bigger on all sides to fit.

I wonder if anyone had done similar before and what I could use to make the hole slightly bigger. What is the easiest way? I don't own lots of power tools so I am at a little bit of a loss as to how to proceed.

Cheers,

matt.

[Plasticman]

i9f you jhave a hole allready then the job is easy peasy, mark out the size you need ,with luck you will only have to cut 2 sides then,check and check 3 times then use a decent pair of snips, not the silly aviation type though they may work but something like gilbows. taske about 5 mins to do
mm