I thought the topic of PRS licences had been done to death but perhaps that was on another list. If you don't have a PRS licence they will be down on you like a ton of bricks and you will have a hard time proving that everything played or sung at your session is exempt from their licence. You may think the burden of proof is on the PRS but they can make a nuisance of themselves and it will only take one rendering of 'Dirty Old Town' or 'Street of London' for their case to be made.The landlord certainly won't want to waste his time, money and livelihood in court so the simplest thing will be to get a PRS licence. If Sam Smiths won't allow the landlord to do this then you're stuffed.