Strain the beef through a colander, discarding any left-over marinade. Lay the strips on lots of kitchen paper and pat dry with more kitchen paper on top. Heat the oven to 50C, or as low as your oven will go (it needs to be a fan-assisted oven to dry out the meat) and put a tray at the bottom to catch any juices. Select 8-10 of the longest strips of beef and push a metal skewer through the end of each strip so that they all hang in a row. Put the skewer directly on the oven rack towards the back of the oven with the strips evenly spaced apart, hanging down between the bars. Repeat with the remaining strips of beef, putting the shortest towards the front as these will require the least heat to dry. Wedge the door open to allow the moisture to escape and dry the beef in the oven for 3-5 hours. Check the smaller pieces after 3 hours – the jerky is ready when there’s no pink left, the meat has turned a very dark brown (almost black) and feels gnarly and firm with just a little give when pinched.