Hi Tereasa,
Yes, there is more legislation/risk assessments/child protection/different/additional observations required -- but these should be in your policies and procedures.
So, to start with perhaps you can familiarise yourself with these - ask if you can have everything emailed to use - so you can read up when time permits.
The EYFS has come in since you were last working - get hold of your own pack - order it from teachernet (link below). There's lots of publications - better to get the pack in hard copy, and you can order anything else. It will only let you order items from 'your' sector - but you will have to register. Most publications are free, if not they are free to download. The more you read the pack and are putting the curriculum into practise, the more confident you will become.
http://publications.teachernet.gov.uk/
As you are in a supervisory position - do you call any meetings? If so, study with colleagues a topic each month/half term etc about schemas/ theories and theorists/ observations/learning stories/brain development/attachment/training/team development etc and all the other things that you may think is done differently since you left(or you just want to refresh).
If you do not call the meetings, bring this up at the next meeting where others can hear, they may be thinking the same. Use that word 'reflection', say you have been reflecting and you feel that you would perform better if.... this can only benefit the children...
Your manager should reflect her own practice, and provide the facilities for that to happen.
Children haven't changed, but our understanding of them and the way we deliver the curriculum has ( efys).
Of the children's behaviour, you mentioned, either you can tackle this yourself (or with support) through stories/songs/ role-play/talking about feelings/ appropriate behaviour/kindness.
Setting some golden rules, praising good behaviour. I am sure you are already doing this, but if you are not feeling confident (or are given no support) suggest to your manager that you would like to go on a Behaviour management course. Everyone there will be there for the same thing - they all want postivie behaviour in their setting, you'll all learn, have handouts, swap tips and come away ready to start afresh.
I'm not sure online courses would help give you that confidence that you had when you were last in the sector. It's much nicer to deal with humans (if you have a choice) saying well done or keep going. When someone is in front of you, you can always ask that extra question until you understand something.
Have a word with your county Early Years and ask them what's on. You should have an advisor that is allocated to you if your setting gets government funding - speak to them, either when they visit. ring or email.
Try and attend forum/meetings with other settings, to see how they go about things and hopefully it will ease you back into the sector.
I'm certain there's plenty of other thought out there. I hope something above is of help to you.