Yes, the snapping function works, many thanks; and Mike, yes I was grouping the doors - in fact it's easiest to group one and duplicate, then group those to make four, then eight etc.
The next issue (and sorry if this has been covered before) relates to the pros and cons of cutting direct from Inkscape versus saving as a DXF file and importing to Silhouette. Take a coach window for instance, with rounded corners done as a modified rectangle in Inkscape. It will cut directly but with little or no influence on blade pressure so you have to cut several times and punch out (using 10 thou plastic card); but if transferred to Silhouette as a DXF, I lose the rounded corners - but have the greater flexibility over cut parameters.
Is there a way round this? I seem to remember there was a 'controller' being developed for use with Inkscape - option greyed out on my version - but has anything resulted? Why is the rounded corner detail lost in the DXF conversion?