Without wanting to put a dampner on your visit to backalleymusic, I've found that some big stores tend to neglect the guitars on show. They can be dusty, extremely out of tune and very badly set up (if at all).
I left Glasgow's largest guitar shop disgusted at the state the instruments on show were in.
I guess what I'm saying is be aware that this can happen. A lot of large stores are not interested until they see the cash. Mind you, £400 is quite a wad so they may be nice to you.
Also, if you have any niggly wee doubts about any guitar don't let them talk you into it. Be totally satisfied with your choice. And if you're not, go elsewhere.
Sorry for the negative vibe and all the best when you get down to it. I love guitar shopping!
Is anything really made up of zeros and ones??