Evidence bag supplier?

Hi All,

Can anyone suggest a company that sells tamper proof evidence bags large enough to hold a Mid Tower PC.

I've been searching the internet for a while now and it appears only S/M/L bags are only available.

I would preferable like an evidence bag similar to the ones used by the Met Police UK as follows

https://www.sellesmedical.co.uk/store/product/2139-Police-Evidence-Exhibit-Bags-

But big enough to hold a PC, and potentially a company who will assist in printing a customisable label.

www.securitybag.com do not appear to be able to asssit. Any UK suppliers out there? Anyone knows who supplies the Met?

Thanks.