I think that system will work together very well, but I'd question whether you need to spend as much as that on an amplifier. I'd be thinking more along the lines of a Rotel RA-04 (£250) or the Pioneer A-A6-J (£350), either of which would be more than powerful enough to drive the Monitor Audios in a room of that size.
Regrading stand top-plates, it's sensible to get stands with top-plates fairly near to the plan dimensions (width x depth) of the speakers, but most stands will have smaller top-plates than this. The use of upward-facing spikes or blobs of Blu-tack will hold the speaker in place.
The BR2s aren't huge, at 19cm wide x 25cm deep - they'd be fine on stands such as the Partington Trophy (top-plate 16.5x16.cm) or Atacama's Nexus 2 stands, which have a top-plate around 14.5cm wide.
Consulting Editor, What Hi-Fi? Sound and Vision / whathifi.com
Audio Editor, Gramophone