I would suggest teak, and I would also suggest eBay. I've bought
hardwood furniture in the past which wasn't teak and never will again.
"Hardwood" covers an enormous range of woods, some of which are more
suitable for our climate than others. There is a very good seller of
teak furniture on eBay. I would post their name here but wouldn't want
to run the risk of being accused of plugging them!

As for the greenfly you could always try some kind of organic control,
like a soap based spray. I'm sure Google will be able to help out with
that one!