What hours are you needing... looks like 0730-when? Consider the typical finish time your nanny would have - it isn't a problem if you get home sooner... nanny can continue working or you can let them go home a bit early (helps build up brownie points, for when the trains get delayed and you end up getting home late).
Would avoid too much juggling around if I were you... as what would happen if school/breakfast club/after-school club was closed, what happens in school holidays, what happens if your children decide they want to do some kind of activity after-school such as swimming lessons, dance lessons, rainbows/beavers etc.
If 7.30am-6.30pm, then let's say nannies wage was £10 gross an hour (not unrealistic for outside London I feel, though you can get a feel for local wages by looking on nanny recruitment websites). So £110 a day. 5 Day working week. Based on 2860 hours per year, gross salary of £28,600 per year. Payroll Calculation by ListenToTaxman.com Employers NI is nearly £3,000
So Salary plus Employers NI, plus the services of a Payroll Admin company puts the cost up to £31,715
Weekly expenses kitty (for activities/outings) - lets say £5 per day, so let's call it 250 working days per year to keep it a round figure (this would thus be a little higher than actual, though around £50-£100 annual difference) Kitty = £1300 On top of that you may pay for some more costly activities, such as swimming lessons, music lessons and the such-like... but those are of course very much optional and if you do them you would probably be doing them regardless of having a nanny or not.
So running total so far £33,015
Nannies travelling costs whilst on duty will vary from situation to situation. If nanny uses their own car, then employers would usually reimburse the cost at £0.40 per mile (this is known as the Approved Mileage Rate). How many miles your nanny does will vary. I do quite a lot, around 4000 miles a year so a cost of £1600 a year.
How much travelling around would your nanny be doing... I don't know. One advantage of a nanny is that they can take your children to places of interest - museums, sculpture parks, country walks, farms, historic buildings, steam trains, water mills, all sorts of places. I've been know to ask a child to suggest a theme... 4yr old says Helicopter... so we find somewhere he can sit in a helicopter. Not all 4 yr olds can say they have been in a helicopter (even one which doesn't fly!) If you restrict your nannies mileage, it can restrict your children's desires to understand the world around them.
So lets add £1500 for travel, pushing our running total to £34,515
While your nanny is on duty, you give them food and drink. Nannies don't really get a lunch hour, can't leave your children home alone. So food is seen as a sort of perk in compensation for working without a break. How much does that add to your weekly food budget... I'm not sure. Nanny will eat with the children, so eat the same thing. If nanny wants something different, I feel nanny should be buying that themselves. So increase in food bill, extra £3 a day maybe? Heating/Light will also be used more as nanny is around during some of the day, so another few pounds. There is also some additional wear and tear on the property. Shall we lump all these types of cost together... call it £10 a day. Is that too high, or too low?
Using the working days figure from before (250 days) which is a bit higher than actual, as nanny would be having more paid holiday than that, if £10 a day is used as a rough figure for food, heat, light, w&t, misc costs then that's an extra £2500 a year.
Our running total is now £37,015. Lets call it £37k.
So I would say a nanny working 55 hours a week, will cost you as the employer around £37,000 a year.
Anyone have any views on that? Is the figure realistic?