Season both sides of the meat with salt. Combine the cream cheese with the gin, spread onto the inner surface of the meat, layer the air-dried meat and spinach on top, roll up tightly. Tie the thyme to the meat with kitchen twine. Brush the meat all round with oil, place on a baking tray lined with baking paper.
Roast for approx. 25 mins. in the centre of an oven preheated to 220°C. Turn the oven down to 170 °C and cook for a further 45 mins. Mix the potatoes, thyme and oil in a bowl, season with salt. Arrange the potatoes around the meat, return to the oven for approx. 45 mins. until cooked. Baste the meat and potatoes with the juices twice. Combine the maple syrup and gin, pour over the meat 5 mins. before the cooking time is up. Remove the meat, cover and leave to rest for approx. 10 mins. Carve the meat, serve with the meat juices and potatoes.