I really enjoyed having dinner at Hamersley's a few weeks ago. The service was absolutely great - friendly (without being intrusive), quick (but not dismissive), attentive and efficient. It's not cheap, but the food is really good and worth the expense.
The place has a great atmosphere - warm but not overwhelming. It's a busy place (deservedly), so there were lots of other diners there, enjoying good food and conversation, but it was never noisy, stifling or unpleasant.
As for the food, I thoroughly enjoyed the olives (my starter) and roast chicken (main course). Everything was cooked and presented beautifully, and tasted great. Several of the colleagues I dined with had (and loved) the seafood paella, and one of them had the salmon, which he also loved.
Highly recommended restaurant.