Has anyone been - is it worth the £9.50 ?

It`s under Earl`s court !

Where exatly is the exhibition and is it on now? is there a website with dates/times/costs etc?

http://www.doctorwhoexhibitions.com/earls.html

i went in april. its quite good, props from each series. it's own dalek 'show' room. they also have a projector type thing which projects you into the tardis (cant really explain it)...tbh the series 1/2/3 props have been in manchester exhibit like face of boe, donnas wedding dress etc. it does have a lot more than the other exhibits have had. worth a visit.