Hi,
a question for the tiling experts out there!

The gap between my kitchen worktop and the window ledge is  175mm and I'm using 100mm tiles with a 4mm spacer. Would I put the full tile along the worktop and the cut tile up to the window ledge or the other way around? Basically, what's best practice?

Btw...the window sill will be tiled also.

If you make the bottom row full size tiles then the next row up will probably have L shape tiles in the corners of the window. Check the dimensions of those L shape tiles because very narrow tiles are a pain to cut. If one leg of the L is narrow then it's a nightmare I find.  You can effect this by choosing to put either a tile or a grout line in the dead centre of the window opening. If you start there the L shape tiles will be symetrical (eg both same size and mittoe image of each other.

If you don't like cutting L shapes make the bottom row of tiles the cut row and that will get rid of the need to cut L shape tiles. What I'd do is fit a batten to the wall and tile the second row up first. Then when set remove batten and cut bottom row of tiles to fit the gap. If the work top and window are level they will all be same size but best cut one and then try to find the best place to fit it. The cut edge should be at the bottom.

Sorry to keep editing this. Got kids on the way to bed distracting me.