Forgot to mention that If I'd covered the top of the cauliflower cheese with some bread crumbs it would have been even better, adding that crunchy texture needed to complete the dish and with some additional steamed veg on the side it could have been a complete meal. Instead it was part of a Monday roast.
Who needs a Sunday roast when you can have one on a gloomy Monday. I didn't use a whole chicken, just thighs and drumsticks (the leg meat is far tastier than the breast anyhow), this means the meal cooks so much quicker and you don't need a whole day to prep, eat and digest the meal. It went down really well with a few glasses of Bordeaux.