As some posters have already pointed out, these young people (always men in my experience) are Nottingham Knockers’. It’s a scam, the young men are bussed in to Cover a specific area then get out.
They are also scoping out potential burglaries. Use your local Facebook page to give warnings to neighbours and report to your local police area.
Another silly little ABC game - shops we have loved and lost?
What is a reasonable minimum spend for an online grocery delivery??