Many manufacturers will have to guesstimate how many RHD cars to make as the RHD versions are only sold in a small number of countries compared to LHD, these wont be converted back to LHD and resold if the UK versions dont sell, they will be stuck with them. So some will have maybe made more than they sold and now need to move them on.
I don’t believe manufacturers work on that principle of guessing how many cars to stock pile, especially western manufacturers, who moved to a Just In Time principle along time ago, so will work on a factory order basis after the initial push for a new model.