i've just come out of a 3-year nanny share. in fact i hope we're about to go back into another one with the same family, but swapped around so that we are now the employers as we want more hours than they do this time around.
TBH we had it easy as we just paid the other family. for a short while it was a 3-way share (before Ofsted registration was an issue, which says 2 families maximum) and we paid the employers but the third family paid the nanny, as they only wanted a few hours.
I was certainly planning to remain the single employer, with the other family paying us, as TBH I felt the employing family were always the nanny's priority (and quite rightly since they were paying all the tax etc!) - I would like to be the one who sets the timetable etc. Having said that I may feel differently after having had the hassle of employing for a few months.
We found each other through the local residents' association newsletter. This is unusual but it was excellent, as local is VERY good.
We paid I think half the net hourly rate that the family were paying the nanny, which was a d*mn good deal.
Make sure that if you take on a sharing family that they understand whether they will need to continue to pay their set amount through the nanny's holidays and sick periods. I'd recommend this as if your nanny is sick for any length of time and you are paying her, plus paying for replacement care, this is not a good time to lose the extra cash. I'm not sure about what we would have arranged about maternity leave - thank goodness the issue never came up.
Talk, talk and talk again (to the other family) and when you have talked, put it in writing. Apart from anything else, it's so complicated that it's impossible to remember everything otherwise!
Remember that your children may become close mates with their share 'siblings'. Therefore only do it if you can stand that thought.
I am very evangelical about nannyshares as ours has been so brilliant, but ask me again in a year's time...