Although apparently I was reading on a petrol station sticker that only 10l metal containers and 5l plastic containers are “legal” (according to BP). 
condoms will perish with fuel inside… Animal Liberation Front used to use them as timers for their incendiary bombs during the late eighties!!
You could get one of those slimmish oil resevoirs designed for when you change your own oil. they are bound to be certified for solvent liquids. You can get them on most bikers websites.
go to a camping shop and you can get a litre bottle (Sigg) to store fuel. I have tried and tested them in my back pack for years and it has never leaked without human error (failing to secure the lid!). You may be able to get them in larger sizes too.