When I signed up with EBH (Jan 2014), I was able to make as many changes as I wanted, as long as all the structural changes (like the layout changes to the floor plan you have described) were done before the tender was signed, at no cost. Any layout changes after the tender was signed would incur a fee. This fee of course does not apply to your post contract variations (PCV's), where you make your selections for the colours, tiles, etc, as these are done later after both the tender & contract have been signed, but are done closer to your build start date to ensure that the selections hopefully don't become out of stock due to being superseded (in the case that you have a longer lead time until you build, due to waiting for land registration, for eg).
I made about 25 changes prior to tender on my floor plan, but I've heard of other ebh customers making more.
Hope that helps enjoy your build!
It does, thanks!
Forgot to mention that prior to tender, my plans were redrawn at least 3 times, at no charge, to accommodate the changes I wanted, & I only paid for the extra materials required (doors, etc), but not charged for these drawings prior to tender or any materials charges unless I was adding to the size (instead of just shifting things around).