I've just done our main bathroom which wasn't too bad, but I had been having a nightmare trying to do an en suite because - I've subsequently realised - I didn't know what kind of 'look' I wanted. So my tip is save yourself a bag of time and fruitless searching and know what basic style you want to go for. Get thee on Pinterest!
The only mistake I made was not putting in one of those underfloor electric heating mats. Otherwise I lurve my bathroom because it ticks all my personal boxes: stinking great bath, digital shower, enough lighting to be seen from space but from different sources so it can be adjusted to suit what I'm doing and a 'dressing table' which is actually just a nice shelf, a lighted mirror and a stool but which has revolutionised how I look after my skin (as in, I now do look after it a bit)! I really love spending time in there. Does downstairs really have to be modern? I think as long as colours flow, you can have a different style. The en suite is going to be French rustic, which the bedroom is definitely not, but the colours of the two are going to be the same and similar.