Orchestra standing to play "Eroica"

[Phil Leeds]

Hi,
I went to a concert at Leeds Town Hall last night. They played some Haydn and Mozart before the interval.
After the interval all the orchestra chairs were removed, except for the cello and double bass players, and they played Ludwig's Eroica. It was a marvelous performance but was wondering why they decided to stand up to play? By the look of some of the faces of the orchestra it might have been a surprise to them too.
Any ideas? - was this how it was done in Beethoven's day perhaps?

[Peter]

Well some HIP ensembles do perform this way (such as Freiburg Baroque Orchestra), but I don't recall that in the BBC production 'Eroica'. I suspect it depended on the size of the venue as much as anything else. Interesting and I wonder if anyone else has more information?