Hi I wish to remove a double glazed window (115cm x 97cm) in an outside wall in my bathroom, block up approximately half (length) replace the remaining hole with a smaller double glazed window with a view to fitting a shower over my bath on the blocked up section. Could anyone tell me the order of progression and what is required. obviously the window comes out first, do i continue the contour line of the existing cavity wall,there is a lintil in situ and plan to leave that in place !? do i need to fit a dpc around the blocked up section? do i need to fit wall ties ? and other than ensuring the new window is fitted squarly,and filled with expanding foam around the sides aqnything else i need to beaware of. I appreciate i have asked several general questions but would like a list of what i should do and in what order, many thanks.