Help me design my teeny weeny bathroom!

[Beetie1]

I have a very very small main bathroom which is in urgent need of ripping out. It currently has an electric shower that dribbles over a bath. Pic shows the current layout and dimensions (yes the sink really does overhang the bath and the radiator is behind the door so currently the door doesn't fully open!)

We plan to replace the bath with a shower cubicle. I don't know what size or shape but it would need to have a sliding door.

The dilemma then is where to position the toilet and sink. The shower can only go in the bottom right corner due to the door and window. If we keep them where they are then I don't think there will be enough room to access the top right corner so it will an odd wasted space. I'd also like to reposition the radiator. Any ideas?

Here
www.al-murad.co.uk
They were quite cheap too!

Our shower cubicle is tiled up to the ceiling in big grey rectangular tiles, the walls are clad in DF waterproof panelling that is then painted and the remaining walls are just painted.

Latest plan is exactly what I was thinking of and would work really I think. Definitely go underfloor heating plus heated towel rail (rather than radiator) if budget allows!

Could the door open outwards, or be a sliding door on the outside of the bathroom?

We have fitted two Kinedo showers and they are fab. Not sure if they would come in the size or shape you need but you could take a look. We chose them because We were fed up with tile grout becoming discoloured, sealant going black etc. Kinedo is built from whole glass panels, there is no sealant.