Roof lantern query

[Fab14]

Hi All, first time poster, so greetings!

 

I was wondering if there was any insurmountable reasons why roof a lantern cannot be installed directly onto a cavity wall with a wall plate, coping or some other such capping. 
 

To provide a little more context the query - I have the conservatory in image 1. that is now 21 years old, therefore at/approaching the end of its service life. To that end I was thinking about the viability of organising a design to increase the height of the dwarf walls , introduce aluminium heritage doors to the front elevation in a designed goal post frame, all to receive a roof lantern with blue glass which seem to be available in the required size and more economically priced than a replacement conservatory roof, bespoke aluminium roof bar equivalents. Only over seen image 2 that looks something like what I envisage in terms of the roof. Any thoughts would be welcome 

 

Note. BC and planning considerations are secondary at this point. Have had initial conversations with both that suggest that some iteration of what I would like to do (which is to retain and reuse the foundations walls and slab of the existing conservatory to create something more robust and aesthetically pleasing still with a glazed roof) will be allowable if supported with the right calcs, foundation tests etc etc.

[gaz_moose]

dig down and see what your conservatory foundations are like.