Glass splashbacks are expensive especially made to measure sizes. Upstands are normally either 70 or 100mm high so that is well above the norm.

If it’s a holiday let I can understand you not wanting to pay a small fortune. If you paint the doors a pale sage green that would look nice. Perhaps paint the ’upstand’ the same colour. As long as it’s not too dark as it has a black worktop.

This image shows similiar materials and flooring. The cupboards and splashback look to be a colour such as F&B Dropcloth or similar. I would leave the upper cupboards the colour they are and replace the tiles behind the cooker with something like a patterned one.

Yes there are similarities with that picture. I don't think I want to change the tiles behind the hob given the limited time we have - perhaps next time around.

As it’s a holiday let i would just paint the panelling with a good eggshell or satinwood in a cottagey colour like an off white, soft sage green, baby blue or a lovely soft taupe. The cupboards look in very good nick so I would leave them. Can’t go wrong with white! Then paint the walls in a similar shade to the panelling.

Oh, paint it. Personally I’d paint it a dark grey similar to the worktop so that the line between the two disappears, if that makes sense. It will tone well with the floor and make a lovely backdrop to simple accessories. You might need a fair number of coats, but I have had something very similar in two houses now—including behind the hob—and it has proved very resilient and easy to clean. Also, the wood provides a nice surface for sticking stuff to as the seasons change. I put tiny little Christmas trees (card decorations, really) on the border and this time of year. In the past I’ve stuck everything from ceramic plaques to pretty paper plates.