"planning a weekly activity programme in line with the EYFS"
What do you mean by that? Think about this, are you really wanting someone to do formal education with your children given their current age? Would it not be better that someone did child led activities, encouraged your children to develop their current interest/play schema. Do you really want it planned out in advance - your children may not want to follow the plan.
Whilst EYFS does mention quite often about Child Led activities, if your nanny is planning a weekly programme, how much of that would in reality be child led? I would suspect a lot would be adult led... is that what you want? Or do you want something else? Are you wanting perhaps just someone who will consider what things they are doing each day and how those things can be educational?
I didn't have much of an idea what I was going to do today at work, I never do... I go with the flow. Some parents may not like that idea whilst others are more open to letting young children have an interest in what they want at that time. Today we went swimming, invited 3yr old's friend - as the 3yr old I care for talked about swimming and when I dropped older sibling at school I bumped into 3yr olds friends mum who said her son had mentioned swimming, so it was logical to suggest we both went to the same place. When we got home, 3yr old wanted to make cakes - so whilst baby slept, we made cakes - he loves to crack the eggs and count things.
We didn't do formal learning... we did learning by doing. Sinking/floating, getting dressed/undressed, interaction with other children and adults, following rules (the swimming pool life guards like to blow their whistle when a child tried to go up the slide), talking about what ingredients are used to make a cake, how we weigh things, what happens to eggs when they are mixed, learning to pour eggs slowly into mixing bowl, how to make cake mixture a bit more runny so we can get it into cases, counting out the cases, separating cases, how white icing becomes yellow, what happens to icing when it is left in the air for a while. Children learn all the time, does it need to be formalised?
In the past we have done numerous things on the spare of the moment, from visiting castles to finding somewhere the children could sit in a helicopter (I couldn't find one they could really fly, that's a bit tricky, but the next best thing for them was to sit in a real helicopter and pretend to fly it). If I was to have planned it, it probably would not have happened as I may not have thought of it. Instead I listened to the child and they said using one word what they wanted to do - helicopter. Castle. Train. Whatever it was that took their fancy that particular day.
Your children will soon start school where they will do more structured learning. You may enrol them in pre-school in the year or so before starting school. So the early years may be the only time they get to choose what to do themselves... if you have a child who loves castles, shouldn't your nanny try to take them to visit one?
Consider how important this planning of activities is to you, is it vital or are you just after a nanny who will do various activities with your children during the week?