Just to keep those interested in this thread up to speed, ESPECIALLY MARKv and Mcbee who were so helpful.
Yesterday Oxa took over my PC using teamviewer and found a huge memory leak.
She is now testing the entire set up on her own PC, and found a bug in V7 (not sure if this is confined only to the latest version) which is causing the leakage.
She is trying to solve this ASAP and will advise when this has been done.