I have read a similar story recently, and it was suggested (by a young person no doubt ), that when someone borrows an item, grab your mobile phone, and take a picture of them holding the item to be lent. Hopefully that will stick in their mind, and if they 'forget' you can always show them the picture with the date!
To think that London, or anywhere else for that matter, does not belong to any one demographic
Son’s girlfriend diagnosed with BPD