I've just done a gammon for tomorrow's lunch. The instructions said 20 mins per lb (approx 2 hrs for 3 kg) at gas 4. My recipe suggested putting it on a trivet in a roasting tin over 2 sliced onions, 3 bay leaves, 5 cloves, 2 whole star anise and 2 tsp of black peppers.
Then add 400 ml of boiling water, cover in double layer of foil sealing well round the edges of the roasting dish and roast for 2 hrs.
Take off the foil and save the liquid for soup (or throw it away -not up to thinking about soup at the moment!!) Strip off the rind and criss cross it.
Make a glaze from 40g black treacle, finely grated orange zest, half a table spoon of English mustard and quarter of a tsp of ground cinnamon.
Paint with glaze, stud with cloves and roast again (at 6 this time) for 25 - 30 minutes, watching it doesn't burn.
Smells divine - hope it tastes good.