The prices are decent, if it's the right rifle & scope for you. Both the Walther and AA are quality products, I find the Walther stock dimensions don't work well for me, the AA's anti-bear trap drives me nuts etc. Something that niggles one person is unnoticed/irrelevant to another...there's no substitute for handling and trying out equipment.
The best place to do that is at the Halloween Boinger Bash , which is just down the road from you. £10 for a day might be the best cash you ever spend on airgunning, you'll get to compare more rifles & scopes than any shop and there are often second hand items for sale too. Its a good way to buy-right the first time.
The scope is heavy (24ozs) on a heavy rifle, it's a spec I've owned but didn't like. IR's have their use, but not that often, likewise 50mm objective and whilst AO gives you focus it's a bit of a pain compared to side focus. Try a few different scopes and I think you might find something preferable... probably.
Hope that helps rather than clouding the issue.
ps. You chose the right calibre.