Spitfire likes studios with reverb. Most of their libraries were done at Air - if you think BBCSO is a problem go try one recorded there! It’s used to be a church, and it’s got an uncontrollable crazy reverb (I’m not fond of that). But you can tone it down by going close mics, which of course sound different overall anyhow.
BBCSO was done in Maida Vale which I believe is due to be torn down (or might have already). It’s a big studio so yes you are capturing a bit of reverb. Not much really, I like it, a touch of natural reverb. Nothing like a concert hall like Davies Symphony Hall. My EastWest samples are so dry it’s a little boring, nice to get a little bounce out of the box. You can edit the mix amount in the pro version.
Their next big library will be at Abby Road which is an even bigger studio I believe.