Find a container that fits the beef steak snuggly. Remove the zest from the lemon in long strips with a peeler. Place the zest in a pestle and mortar with the oregano, bay and garlic cloves. Give it all a couple of rough bashes – this helps to release the oils in the zest and herbs and breaks the garlic from the skins. Throw it all into the container along with the olive oil, cumin, cinnamon, and the juice from the lemon. Add the steak and give it a few good turns, working the flavours into the surface. Leave to marinate in the fridge for at least 6 hours, preferably overnight, turning occasionally when you get the chance.
Take the beef out of the fridge at least an hour before putting it on the BBQ. In the meantime, prepare any sides and get your BBQ lit so it has time to settle to a good medium-high heat.
Start by making the flatbread dough. In a large bowl, combine the flour and salt. Add the warm water, yoghurt and olive oil. Knead for a couple of minutes until smooth and elastic, then cover and leave to rest while you get everything else ready.
To make the tzatziki, coarsely grate the cucumber and use your hands to squeeze out as much water as you can from it. Transfer it to a bowl and mix in the yoghurt, mint, garlic and a small pinch of salt.
Place the sliced onions into a small bowl with the vinegar, sugar and a pinch of salt. Leave them to one side to lightly pickle and turn pink.
When you are ready for the beef, remove it from the marinade and season it generously with salt and pepper on all sides. Place it on the BBQ and cook it on both sides for about 5 minutes until nicely coloured. Now shift the steak across to a more gentle, steady part of the BBQ and cook it for a further 15 minutes or so, turning often, until deeply coloured on all sides. Make sure you use your tongs to turn it so that each end and the thinner sides get time sat on the grill bars too, this ensures an even colour and cook. The steak is done when it shows about 55C on a meat thermometer, or when it is starting to firm up when squeezed. Leave to rest for at least 10 minutes.
While the beef rests, divide the flatbread dough into 4 equal balls. Dust a board and rolling pin with a little flour. Roll each ball out as thinly as you can. Slide them onto a hot part of the BBQ griddle to cook. They cook quickly so keep an eye on them and give them your full attention. Turn and flip them once to get a bit of colour on both sides. Keep them stacked to one side when ready.
Slice the beef thinly across the grain and serve it to the table with everything else. To build each flatbread slather on some tzatziki, followed by some tomatoes, red onions and a few pickled chillies. Lay in generous amounts of beef and finish with plenty of parsley and a sprinkle or paprika. Fold and roll them closed and attempt to eat with as much grace as you can manage.