Boots and WH Smith do. You could apply to them. You do not need your NI number as you do not pay it until you are 16. Forget chores for neighbours, your parents would be mortified if you ask neighbours to do jobs for money. Come the Spring, cafes, restuarants, small shops and garden centres employ 15 year olds. There is hope.
JAN should read the UK Working Time Regulations.
Have employed loads of 15 year olds as have every business in the Tourism Industry in the West Country.