I recently visited the Harrow after it reopened under new Management. We booked for a Sunday at lunchtime. We weren't disappointed.
The Roast was cooked very well and the range of vegetables available were good.
Although the restaurant was busy (probably better to book, to be safe!) the wait for food wasn't long at all, yet the food tasted fresh and wasn't dry like some Sunday Dinners who cater for all and let it dry out in the kitchen.
We had an unfortunate incident where a drink was spilt on one of our diner's Roast Beef and the lady behind the bar (who I think was the new Manageress) re-ordered a new meal and only charged us half price for it, which was a nice touch.
I'd recommend for a fussy roast eater!