I visited them a couple of years ago to deliver a few years-worth of Aircraft Illustrated magazines that filled a gap in their collection (and released some space in my garage!) and I was very impressed with the set-up then. I recognised several publications that I used to access when they were at Hamilton Place and I was at ESDU at Oxford Circus (especially NACA TNs - yellow covers visible at 20 yards!)
I've always promised myself a visit to FAST, but not made it yet.
GG