No interactions present.
This is a really nice observation. In South Africa there are 'beetle daisies' (e.g. Gorteria spp.) that have lifelike beetle mimics on their petals that seem to attract beetle pollinators. I think people grow them here in gardens too. It would be fun to see whether our beetles respond, but they are much smaller than the SA ones.
University of Edinburgh and Biodiversity Observatory (OU)
Yes, there are a few different species in the genus Meligethes (I think more than 30 in the UK!). They are all fairly similar but there is a recent key for identification. Your other insect is a Heteropteran Bug - you can tell its a bug and not a beetle as you can see the membranes of the forewing in your pic (in beetles the forewing - (wing case) is always opaque). Not sure of the species though!
Agree with Rob's comments. Meligethes are quite hard to identify to species, and usually not posible to do from a photo unfortunately. And I'm afraid I don't recognise the bug either!
Entomologist and biological recorder
Lat/Lng: 51.860830194634, -0.73707103729248
OS grid ref: SP870187