Get a nice bed of coals cooking. Once they’ve hit core temperature and have started to ash up, then you are good to go. While this is happening, melt your butter in a small saucepan and add the garlic, chilli and thyme leaves (you can do this in the kitchen or on the grill). Once the butter starts bubbling, take it off the heat. Set it aside.
Now let’s cook these things. Blow the ash off the coals, then lay the lobster halves flesh side down on the coals for 1–2 minutes depending on the size of your lobster. Once you have a nice char, gently turn them over and brush with the flavoured butter. Cook for another couple of minutes shell side down, brushing every 30 seconds. The meat will pull away from the shell when it’s cooked.
Leave them to rest for a couple of minutes on a metal tray and pop your butter back on the grill to keep warm. Gently remove the flesh from the tails and claws. Brush again with the butter. Finish with the lemon juice. Toast your buns. Spread a dollop of mayo on the base of the toasted bun. Pile the lobster meat high and sprinkle on the chives.