does anyone know if theres a special war time display there this half term week?

Try asking them the question ;)
http://www.simt.co.uk/contact/index.html

There has been the 'their past, your future' exhibition' on the upper floors for a while. Not sure if its going to run through half term, but it was there last weekend, and it was quite good - lots of people dressed in wartime uniforms as well. :D