Pre-heat your oven to 190°C/Fan 170°C Gas 5. Slice the potatoes into 1cm pieces. Place into a pan of salted boiling water and cook for 2-3 minutes, drain and leave to cool.
Take two slices of the pancetta and lay them side by side. Place the pork in the middle and wrap the pancetta around the pork.
Lay the potatoes onto a non-stick baking tray, sprinkle with the lemon zest and scatter over the sage and tomatoes, then season with salt and milled pepper.
Place the pork on top, drizzle with the oil and bake for about 20 minutes, until the pork is cooked through and the potatoes have crisped a little around the edges.