How can I keep a slow roasted pork belly roll warm while roasting potatoes? I'm hosting a dinner at mine in two weekends time (a first for me!) and have already noticed where my main may not end up as tasty as I'd hope.

I'm looking to roast a roll of pork belly at around 170C/Gas 3, which isn't an appropriate temperature to achieve a nice, crispy roast potato. That means I'm going to have to cook them separately. Does anyone have a good tip on how to keep pork belly warm with a crunchy crackling whilst I roast the potatoes? I was thinking of putting back in the oven but worried it may dry out before that happens. Would it be a better idea to reheat the potatoes instead?

I've been over-reading and don't know what to believe anymore!
It's normal to rest meat before carving, sometimes for quite a long time. 

The oven will already be hot after cooking the meat, even if not quite as hot as you'd use for potatoes. so I suggest you parboil the potatoes (often recommended anyway) and put the roasting tin and fat into the oven to preheat when the pork is nearly done. Then take the pork out of the oven, put the potatoes in and turn it up. The pork should rest under cover on the container in which it was cooked. A loose (tented) foil lid with a tea towel or two over the top is good insulation. If you want to speed things up further, you could turn up the oven a few minutes before taking the pork out. The effect on the pork will be minor (in most ovens) but the potatoes will cook quicker and may be more crispy.  I doubt you'll get very crunchy crackling at that temperature anyway.