You're more likely to have some joy with an Au Pair. It's the 6am start and limited hours that will put folk off. In theory a nice teenager would suit, but need a very responsible one, and they would move on sooner rather than later.
I have someone who does similar to this for me, including collecting one DC from school, but in the afternoons, not early mornings. She doesn't need to actually supervise or care for the DC as they are self- sufficient so she does a bit of ironing, hoovering or changes beds. I pay her £10 ph.
I think the time slot might be problematic although I know that it would appeal to my lady, but If I were you I would try to market to an 'older' person - My lady is retired and so she is happy to work odd hours and doesn't mind getting up early.
if you just need the person to be present in the house in the morning when you leave the house at six, i think an older aupair (rather than a 18 yo superwising teeneagers), might work ok. they could all get up later and get ready. depending on the ammount of housework needed she could then have some free time to go to classes or do as she pleases during the day and be back home for when the children are back from school.
I think an au pair would be the way to go then. They do 5 hours a day usually, so 6am-8am and then 4pm-7pm. I don't thinks 6am will be a popular start time tbh, but because your children are older it should be an easier job in other respects. Would you actually need them to start at 6am or just be in the house? Could you leave them all asleep at 6am and then the au pair wakes up and gets the children up at 7am or something?
An au pair is not a cleaner, but will do light housework (hoover, bit of dusting put some washing on, start the supper etc).
The only issue I would warn you about is that au pairs are generally very young, is your 14 year old likely to do as she's/he's told by a 19 year old? I know some teenagers will be fine, but I know au pairs who have worked in houses with teenagers who say they just totally ignored them/were rude to them etc.
Oh gosh,I read that wrong, thought it was 11 + 4yo, not 14.
Heck yeah I'd leave them if they are otherwise sensible; they would be responsible for selves & each other. But if you could use a cleaner anyway,then I would offer the job up to a local college student and it's not end of the world if they end up unreliable & only staying for short spells, because of how old your kids are, anyway.
You might find it easier to offer the job 7am-9am.
I think if you offer 7-9 (or longer if want more help around the house) & pay £10ph you will find someone. I think the key is going to be deciding exactly what you want someone to be there doing. It might suit one person to be there nagging encouraging the kids to get up/do their jobs/sorting their breakfast and shoving a wash on while they're there & it might suit someone else to be focussed on doing the house work and just being around if the kids need her - they will need to know what their job is, so they feel they are actually doing it, if you leave it all a bit up in the air there wont be much job satisfaction for them and there will be a lot of frustration for you.
if you were offering £10 an hour I suspect this job would really appeal to someone who was used to working as an early morning office cleaner. They usually do 6-8 and it's horrid hard work at the minimum wage, a lighter cleaning load with a little bit of teenager chivvying and tons more money would probably go down really well....