Right, for a reasonable fine dining option that is a short cab ride/15min walk away

Cafe Anglais in Bayswater. Excellent modern English cooking, nice dining room. www.lecafeanglais.co.uk

More expensive haute dining

Angelus, 4 Bathurst Street 5 mins walk. www.angelusrestaurant.co.uk Wonderful modern French cooking but it is expensive. Amazing wine list and lovely bar at the back

Modern Gastropub a 15min walk away through some lovely streets

http://www.theprincealfred.com/ - classic Victorian pub architetcture too

There is a whole cluster of options towards Marylebone of which

Michael Moore www.michaelmoorerestaurant.com modern Brit restarant
L'Autre Pied www.lautrepied.co.uk fab French
Caffe Caldesi www.caldesi.com classic Italian in buzzy dining room
Duke of Wellington www.thedukew1.co.uk beautfiul pub with great dining room

are all very good.

But whatever you do, do NOT eat in the Hilton or the nearby pubs. They are crap.

Happy to narrow that down further!