My favourite Italian in Mayfair is:
Alloro
19-20 Dover Street, W1S 4LU
020 7495 4768
Only a few mins walk from your hotel and depending on wine easily under £50 per head.
If you fancy something on the cheaper end (£15) you're only a 10 minute walk from Soho and you could head to Busaba from great thai food
Busaba Eathai Wardour Street
106-110 Wardour Street, W1F 0TR
020 7255 8686