I went to the Hawksmoor for the first time last weekend so here is a very short review:
Room: As if Jules Verne designed a train station in 1920's Chicago; it is wholly underground and I felt strangely claustrophobic during my meal, though it is still a great looking restaurant. I think the room is better suited to nighttime than to a Sunday morning meal simply because it is dark.
Service: Waiter was proficient, but instantly unlikeable There were three of us dining, and we each ordered the roast, though I asked if it would be possible to substitute the roast potatoes for mash. He was very hesitant about the prospect of this substitution and tried to talk me out of it, though once he approached the kitchen there was clearly no problem as my lunch arrived sans roast potatoes with a side of mash. He also forgot my chips (which he also tried to dissuade me from ordering) which was annoying because once I reminded him they arrived when I had already eaten my mash, and was thus no longer craving chips.
Food: We only ordered roast beef so cannot comment extensively, but found the meal to be good, but on the heavy side. The meat was very gamey and the portions were almost too large; they used a rump roast which isn't the tenderest cut of meat so their cutting the beef slices close to an inch thick made cutting off bites a fair effort. At £17.50, the roast was the cheapest beef option on the menu (and the cheapest cut), and I thought they should have offered a rib-roast as well. The sides were absolutely amazing; the cabbage was almost worth the cost of the whole meal, as were the mash and other veggies.
Conclusion: I would return and have a steak, but not the roast. I also have read the burger is amazing, so will certainly return for that!