One doesn't even have to carry out a full Demeree , often I find a partial vertical split is enough. Simply remove the open brood upstairs and the bees will divide them selves up.If they start charging the QCs, then they are already in swarm mode? There were a lot of play cups all round the edges of every frame. This colony was quite swarmy last year so I’m thinking I split them now and I can always reunite and have a spare queen for another colony if needed. But agree a demaree might have been better.
Leave the Q in place with the sealed brood and with a good half dozen drawn or foundation frames to keep the bees busy.
If the colony isn't on double brood then that would be my first option to give plenty more room, I find my queens will lay up to 18 brood frames and be quite happy . Improving ones lot is the easiest way to weedle out over swarmy traits though at some stage they will produce swarm cells to replace an older queen in her third year if pheromones are reduced, once one improves the swarmyness trait one can then rely a little more on late season superscedure with two or three cells present.
Apart from a casual tilting of the top BB to look between my colonies for any signs of QC's , the conditions just haven't been good enough for a proper rummage thru. It has either been raining, a cold chill wind blowing or both. Finally Saturday and most of next week the forecast looks quite good with some spring sun and mid to upper teen temps, so may get a first proper thorough inspection this year.