Teenieleek @12, you asked an interesting question about where the down clues start. Actually, the knowledge that the grid has 180 degree symmetry gives you a very good idea. The first three across clues are 5, 7, 5. That means the last three across clues must be 5, 7 and then 5.
Actually there is only one place after the start where there is a 5, 7, followed by a 5. The final 5 would be clue 22, which would mean an even split, as there are 44 clues. So a good working hypothesis is that the clue beginning “Provide vehicle …” is the last across clue.
And the fact that it’s a 12x12 grid and the first two clues would fill the top line supports it.
Sorry if it sounds technical, but the mention of symmetry is always an invaluable way in