Hi Rich. My slight concern with your conundrum is that you've been told by someone else - so it's second hand info at best.
Disabled people and benefits claimants are routinely scrutinised and judged for stupid things. Be a wheelchair user and get seen transferring or walking a few steps - someone might report them even though the DWP know person can walk a few steps sometime... I have two wheelchair using friends who are routinely reported to the DWP, one by a malicious neighbour who thinks friend 1 is a faker cos they moved their legs while in a wheelchair (common scrutiny issue). Friend 2 gets reported because he dares to challenge inaccessibility on the transport network.
I often get people whispering at me about how I'm clearly a legit disabled but A B or C is totally dodging the system. Sometimes I know A B or C and realise the outsider has no idea about their reason for claiming benefits and just has gossip or nastiness to explain why they think what they do.
How does your source know about this fraud? It strikes me as a bit dubious given foodbank food would probably save at most £20 a week and that wouldn't go far towards an expensive holiday. Most foodbanks have a limit of how often people can go, and others have referral systems (which in themselves can be problematic because not everyone can get a GP/jobcentre/social worker to refer them. And I suspect some foodbacks expect people to scam them cos scum. I remember school trips when they became "voluntary" to pay for, and one of my sister's richest friends' parents said "Well I'm not paying then". They were the type to have the only Tory signs all over their garden at election time! My mum was appalled, especially as she knew families on benefits were putting coins in jamjars to pay as much as they could for school trips. Some people are just horrible (and or Tories).
Even if Rich/someone was to report this to the foodback, they'd probably have to assume it was a malicious report given how prevalent malicious reporting is. Foodbanks will know you can't tell someone is poor because they keep themselves smart and clean and are very very ashamed or scared of social services taking their kids away etc.
If someone told me they were scamming a foodback or similar I'd probably ask them why were so selfish and remind them that many donations come from people rather than businesses and they're potentially stopping a legit poor person from getting food which is a pretty scummy thing to do... I probably wouldn't report them cos I don't think it's worth it, but I would avoid them from then on.
It is difficult tho, cos we want people not to be vile. Sadly some small % of people are vile and I think we're better off supporting the 99% legitimately needy rather than erecting more and more barriers to stop that 1% at increasingly diminishing returns and indeed reducing people claiming at all. Most social security is under-claimed, as in people who are legit, don't claim cos it's too hard.