Affixing trailer mirror?

[BeckyD]

I have bought a large acrylic trailer mirror but am unsure of the best way to affix it. I found something on the internet saying to attach it to marine ply and then fit the whole lot to the trailer, but marine ply is really heavy so I wondered if anyone else does anything different?

In case it makes any difference it's attaching to a fibreglass CL trailer...

Thanks in advance if anyone is able to help xx

 

[Law]

I used millions of those number plate adhesive pads and alcohol wipes to clean the surface first. Two mirrors have stayed on but one worked loose and I have got some special strong glue for exterior fixing from Focus. It comes in a big tube for about £9.
As it is I've not bothered putting the mirror back up yet as I've not needed to.

 

[BeckyD]

Great thanks for the suggestion! I think there may well be a trailer|Becky|mirror sandwich this weekend as I'm hopeless with glue