Replacement band clasp for silicon 5S

This seems a daft question but it's the sort of thing I'm sure is easy to waste time and money on so thought it worth asking here. I have a Fenix 5S with the original black silicon strap and the clasp that the excess strap tucks into has broken and fallen off so I need another. I thought it may be easiest just to buy another watch strap and have spares for the rest of it but on finding they're £45 that idea is out the window. There are cheap non-garmin straps I was thinking I could give a go or is there a generic part which does the job?

Thanks,
John