You are well within your rights to refuse them. I do not let people come into my home without being given adequate notice.

However, if they were friendly agents I probably would have if I knew they would turn a blind eye to the mess (there's a big difference to an untidy home to a dirty home). Our home is often untidy but I know that it's "clean" underneath the washing, toys and school books!

With regards to the maintenance of the front garden, I think you'll find this on your lease. It is the responsibility of the tenant to maintain the upkeep of the property, ie, mowing the lawns and weeding the garden. Some tenancy agreements will cover additional items but, as I say, this should be on your lease. If you don't have a copy, you can request an additional one.