Please help me sort out childcare needs - nanny or au pair?

[spritesoright]

I am currently home with both girls 3 days a week and DD1 is at nursery 2 days a week. I wasn't planning on going back to work (had nothing lined up) but suddenly a great opportunity has come up.
Unfortunately it would be full time and sooner than I had hoped but I don't want to pass it up. DD2 will be 11.5 months and DD1 will be 3.5.
It is unlikely that the nursery will be able to accommodate both girls 5 days a week (this is 3 months away). So we thought we could do 2 days at nursery both girls and 3 days either a nanny or au pair.
Obviously an au pair is appealing so that my entire salary isn't eaten up by childcare costs but I have some concerns.
First, I've read that au pairs can't care for under threes but I don't know how this is regulated (and by whom).

Second, I am wondering if it would be stressful to have someone living with us and having to deal with day to day living arrangements. We are also planning basement renovations so she would be in the spare room and all sharing one toilet
Lastly, I'm wondering if it is too much for an au pair to care for a 1 and 3 year old for three full days a week. I find this difficult. How would she cope?

I think I've kind of answered my own question but I would be interested in any insights/experiences.
Has anyone had a similar arrangement with an au pair that worked or would I save myself a lot of stress and worry by hiring a nanny?
Thanks.

That's not an au pair role at all - they are untrained childcarers and need a lot of help and support in the early stages.

Our current one is excellent - but I would never leave her with a little baby, you need a proper nanny for someone that small.
Au pairs also need time off for language classes during the daytime.

I also think all of you sharing a bathroom would be too much.

Maybe it is something to think about when your children are older but for the time being you need a nanny (or a childminder +preschool for the older one)

Agree with everything karoleanne has said

I had a nanny for four years - switched to an au pair plus when DD was at nursery (aged 4.5 years) and now have au pair as both kids at school

And having had live in au pairs for 8 months there are undoubtedly stresses

We have a separate bathroom and this deffo makes this much easier although of course it is manageble with one bathroom

Personally from a parental view I wouldn't use an au pair for an under 2 I just feel they would need someone qualified.
Check with your employer and see if they do childcare vouchers. If you get an ofsted registered nanny then you can use vouchers to help pay.

Okay, that is kind of what I thought but I just needed some confirmation. DH wants to get an au pair because it's cheaper but I think in practice it would be me training her and dealing with the fall out if it was all too much for her (which it sounds like it would be).
It is frustrating to go back to work for essentially nothing because my entire salary will be eaten up by childcare costs but I will have to see it as a temporary situation and investment.

donkir that is really helpful about the vouchers. Also, DD will get her 15 hours free by then and the nursery offers 10% discount on second child.
DD1 has been at this nursery since she was 1 (although not full time) and really thrived.
The drawback of course is that DD2 will have to adjust to two separate scenarios.

www.bapaa.org.uk/displaypage.asp?page=41

This page is useful information for families looking for an au pair.
It says Au pairs should not care for children under 2 years.
I suppose should a serious accident occur you could be charged with neglect as parents. Unlikely I would think. Have a friend who had an au pair for babies used older girls late 20s. Helped friend from same European country as Au Pair so no language problem.
Could the baby use Nursery for part of extra days to reduce Au pairs time.
Think it could work if you restrict hours to just 3 days so other 4 days she doesn't work.