Pre-heat oven to gas mark 6/400F/200°C.
Pick the thyme leaves off and discard the stalks and finely chop the leaves.
In a bowl, put the knob of butter and add half of the chopped thyme and the grated garlic and give it all a good mix.
Lift the skin of the chicken with your fingers and push the herbed butter underneath the skin (you need to be very gentle as to not tear the skin).
Season the chicken well inside and out.
Slightly warm the honey in another bowl.
Split the vanilla pod lengthways and scrape the inside with the back of a knife and mix into the warmed honey.
Add the remaining chopped thyme into the honey mixture.
Place the chicken into a roasting tray and pour the honey mixture all over the chicken and pour 100ml of chicken stock into the tray.
For the roast vegetables, peel the swede, parsnips and carrots and cut into equal sized chunks.
Peel the onion and cut into wedges.
Pick the rosemary leaves and roughly chop them.
Toss all the vegetables in a little oil, add in the rosemary and season it well and place them in another roasting tray.
Cook the chicken in the centre shelf and the vegetables in the bottom shelf.
The vegetables will take about 30-35 minutes to cook (but the tray needs to be shaken and vegetables turned over every 15 minutes but be careful not to break them).
The chicken will take about 1 hour to cook, basting it with the juices every 15 minutes as well.
Meanwhile, to make the mash, peel the potatoes and chop them into large chunks and boil them in seasoned water until soft.
Mash the potatoes and add the butter and season it well.
Pass it through a sieve to get rid of any lumps and cover to keep warm.
Once the chicken is ready, remove from the tray and transfer onto a serving dish. Cover the chicken with foil and let it rest for 20 minutes.
Using a spoon, skim off the excess fat from the juices in the roasting tin and then add the remaining stock to the tray, scrape and mix with the juices.
Pour the juices into a saucepan and bring it to boil for about 5 minutes.
Whip the cream lightly.
Add 2tbsp of the whipped cream into gravy in the saucepan and when it has warmed through remove from heat.
Strain the gravy into a serving jug.
Add the remaining cream to the mashed potatoes and mix in thoroughly. Re-heat if necessary in a pan or in the microwave.
Transfer the roast vegetables into a serving dish.
Serve all together and carve at the table.