Just the basic foamcore structure so far, I borrowed some silicone glue substitute from my parents who make cards, and who recommend this glue for card craft as this was the ideal situation to give it a try on foamcore and see how it performed.
The glue is called Pin flair glue gel and it seems to be doing a good job. I have put it aside overnight to dry fully but the structure seamed quite solid after an hour when I went back to check that nothing had slipped out of place.
UPDATE 25th Feb : As I had to edit the post to insert the name of the glue I will take the opportunity to post a quick update. The glue has fully dried now and the bond is very good indeed I have removed all the pins that I used to hold it all in place while the glue dried, and there is no movement or loose joints. I will definitely look at buying a tube of this glue to see if it has other applications within model making.