What about giving them a scenario with your children in mind and asking them to write how they would react/cope/diffuse the situation, this might help you get to know their way of thinking and whether it's in tune with yours and also how good their English is if they are foreign.
Have you actually paid for membership? If you have, then when you say "Yes, I'm interested" in response to an application, your email addy becomes visible to the girl. I've found that 50% of the time, or more, the girl will then contact you and you can use that to start a dialogue.
Failing that, I would just try to rank the candidates and start emailing them.
No haven't paid membership yet until I got the hang of things. I won't need anyone until Sept/Oct time so I have plenty of time. But then time goes so quickly and I am not the most organised
Didn't mean to sound dishonest there - obviously, if you find a girl from any of these sites, you should pay your fee to them. But I can help out if you don't want to let a good one get away at this time
I send out a standard questionaire to everyone and then I pick and choose through them. I like to have it all in writing so I can go back and reference what each one said on any particular question. This also serves to test their computer skills, which are very important to me becaus they be able to communicate with me on e-mail.
I found it was good to whittle first with the very basic stuff, like can they start on the date you need-obviously there is no point pursuing it if the answer is no I need a job right now, or no I am in college back home at that date. Can they work at the hours you need or do they already have a course or something to do, too? Also immigration with people who are already here-I had one trying to tell me they are here on a student visa from the Phillipines, and there was no problem about them missing their course since their college was too far away to attend if they took my job-another came from Nigeria on a fiancee visa but wasn't going to marry the chap after all- I didn't believe them. You don't need that.
I think the quickest thing is to do as Uwila says and send a questionaire. That will whittle in itself as many will be incapable of doing it for one reason or another-though lots don't get that much online access at home, not everywhere has broadband. Since you think you want someone already here, don't you, before you fork out to the big international sites, have you tried this one: nannyjob.co.uk, also keep an eye on gumtree you never know who might advertise themselves.
Don't get your heart set on any until you have spoken to them, at least on the phone-these profiles can be very deceiving.