As per your query here I am providing you the lists of things to be considered for a good nanny along with the lists of nanny services located in London. Please check the below details:

The things you should looks up:

Your child lights up at the first sight of her
She comes up with creative solutions to problems and works with you to provide the best possible care for your child
She arrives on time
She makes an effort to stay connected
Your child's room is clean, and so is your child
Accidents are infrequent
Trustworthy
Safety-Conscious
Loving
Enthusiastic

List of nanny agencies located in London where you can hire nannies:

The London Nanny Agency
5-11 Westbourne Grove
+44 7824 314032

London Nanny Agency, Governess agency in London
1 Lyric Square
+44 20 7147 9945

Little Ones (UK) Ltd
3 Hanson St
+44 20 7183 0309

Kensington Nannies
3 Hornton Place
+44 20 7937 2333

Norma Lewis Nannies Nanny Agency
176 Finchley Rd
+44 20 7060 4050

Cupcakes Nanny Agency
13-14 King St
+44 20 7600 9880

KiwiOz Nanny and Au Pair Agency London
London, 25 Lavington St
+44 20 3427 5423

Harmony at Home Nanny Agency Kent
2 Veridion Way
+44 1892 222450

Harmony at Home Nanny Agency London Putney
+44 20 7870 1044

Eden Private Staff
9 Cambridge Court, 210 Shepherds Bush Road
+44 20 7471 6000

Tinies South East London
6 Hay's Ln
+44 20 3691 8828

Tinies
Parsons Green House, 27 Parsons Green Ln
+44 20 7736 5214

Snuggles Childcare
Studio 2C, Clapham North Art Centre, 26-32 Voltaire Road
+44 20 7177 2249

Peek-a-Boo Au pair and Nanny Agency
1 Guildhall Yard
+44 20 3167 0925

Buttons Nanny Agency - London
4 Framfield Rd
+44 20 8567 3112

Nannies Incorporated
Suite 512, 162-168 Regent St
+44 20 7038 3757

Baby Room Nanny Agency
155D Northcote Rd
+44 20 7228 2811

Imperial Nannies
17 Radley Mews
+44 20 7795 6220

Nurturing Nannies Nanny Agency
18 Palace Ct Gardens
+44 845 652 2440