Thinking of approaching them with " we've sold our house and at the end of the lease we will be moving in , but wanted to see if it was convenient for you to leave early . We've been watching the rental market and if anything it seems softer than when you moved in ( it does ). "
Cliff
I would do it through a note in the letterbox and follow that up with a visit, Cliff.
You can't just lob on the doorstep with the news and the offer because they may have trouble getting their head around it and would feel ambushed.
Set it out clearly and tell them when you will drop around to have a chat about it.
I think the letterbox notice is a good idea. Put your number on the bottom so they can ring you when they have digested that they will be moving and possibly add "we are happy to release you without penalty if you decide to take advantage of finding a house now rather than miss all the good ones that will be taken in January" (in your own words, but you get the idea). If they realise (by your informing them) that the peak renting time is January and if they move now they get the pick of what is available, whereas if they wait until May they get the dregs, they may decide to jump now, especially with a rent free period on offer.
I like the idea of the PM finding them something else, and if you can get the PM on board with this, put that in the note too.
I'd offer that once they give two weeks' notice they have found something, as long as it is before xx date, that the rent for that last two weeks is free (or four weeks - whatever you are comfortable with). You'll know soon enough what they think of the offer.
Even though you have a PM, I would want to word it how I want it worded. Chinese whispers can change a message, the nuance of how it is meant to be read. We all know this from this very forum, where messages can be read wrongly, and if the PM doesn't word it how you want it worded, in your favour, then you risk them digging their heels in and thinking "stuff you, I'm staying to the last day".