Hurrah! After four months of waiting, our cracked window has been replaced. They have also put in the metal pressings to create the look of a giant window with six frames.
It is a bit annoying that we haven't put up the glass balustrade on the balcony yet because we thought that they would hoist the window up on the outside of the house, but instead they just took it up the stairs. At least we can get it ordered now.
They have also fitted the window cills, so at last it is nearly all sorted out.
The windows are fantastic and we absolutely love them, it's just a shame that we bought them through such a poor company.