This is normal. Workshops are non-archival and conferences only require that the work hasn't been submitted to any archival venues.

[edit to extend]: Researchers will often submit their work to a conference and one or even multiple workshops in parallel. Workshops are great at getting a more targeted audience and discussion. It's also a strategy to get more people to see your paper.

I'll also give at least £5k if tax deductibility is set up in the UK.