Unfortunately, the Big Bang Fair, which was to have taken place this Thursday 12 March 2020 has been cancelled by the organiser – see link:
https://www.thebigbangfair.co.uk/news/media-and-press/press-releases/the-big-bang-uk-young-scientists-and-engineers-fair-2020-has-been-cancelled/
Refunds will be issued as soon as possible in the usual way.