Shouldn't be too bad, might want to make sure you have a bit of roof overhang on the rear to keep water off the boards or just get some cheap guttering.
Looks like the front will be open anyway so exposed to the elements a little.
Personally I would have put the clear sort of corrugated -- get some light in! Oh also, UPVC facia of some sort. Quite frankly that wood is just going to rot (especially if you have leaks or water running down the side), regardless of the 'treatment' they gave it. Your roof runnout is going to splash the wood at the bottom and it'll probably start there!
Not naysaying, it's a great job, but I've seen quite a few piece of wood garden features rot in a couple of years before...
looking great man, probably the only thing i'd have done differently is raised the wood off the ground with some painted/galvanised box section, will stop the water seeping up from the ground and rotting the bottom out.
These would fit if I removed the bottom board. I would just need to cut them. To fit in between the posts.
http://www.wickes.co.uk/Wickes-Recessed-Concrete-Gravel-Board-50mm-x-150mm-x-1-83m/p/540064
A neighbour would cut them for me. The rear wall board is actually raised of the floor as there is concrete curbing behind it.
In fact the width between the posts is 900mm so one would just need to be cut in half.
Hmmm
Nice work and thank you.