parkview094 - All valid points, although I'm looking at ways to take some doors out rather than add them in. The door to the dressing room in our current house never gets used so we would probably keep it open plan.
Unfortunately we can't mirror the balcony on the RHS as it has a conservatory underneath. But that would have been a good idea. We haven't given up on the RHS option as I think it would give better use of space for bed 4 - as a bedroom you can fit in a double bed and nothing more. We would still enlarge the en suite to the current master as the room layout at the moment is disjointed. But hubby would like to keep the balcony for the master suite.
If we were to leave master where it is we would still make bed 3 bigger use the current en suite for bed 2 as a walk in wardrobe for bed 3 and have the family bathroom as a jack n Jill for beds 3 & 4.
Definitely to the shower in the master en suite - we have a big double shower currently and also a bath (which is used more than the family bath) so wouldn't want any less in the new house.
The master would be very large and like you say maybe too big - but I think we'd still have to have some wardrobes and probably the dressing table in the bedroom. We need (to stop having our clothes dotted around differently bedrooms) 3 doubles each and I'm not sure that many would fit into the dressing room if we kept the master on the LHS.
We are definitely looking to make the bedrooms more even sized. At the moment my daughter is having the 2 attic rooms. We are looking at the huge master and my DS is currently ending up with a box room! So we do need to do something for him also.
The cupboard does have the water tank in but also all the piping for the underfloor heating and something the do with the air source heating so it's pretty much the only thing which can't be moved. It can be made a little smaller but probably not enough to warrant messing around with.
It would be nice to keep the costs down but we would be updating all the en suites / bathrooms anyway so I'm looking at this as extra cost is just the stud walling.
The house is in a beautiful setting on the edge of a lovely village overlooking countryside. It was only built a few years ago, but was built for the older couple who designed it and live in it currently and don't use half the rooms. We're normally new build people who wouldn't dream of taking this on but when its updated and think it could be an amazing space.