HI Georgina,
Thanks for coming back to me, its a shame to see that as we used it quite a bit for our clients, where they moved over from Sage as some of them need to print in very specific ways for deliver notes or waste transfer documents. Thought it was a great function when we saw it removed we were hoping it would be integrated into the software properly.
The way the current design editor works is very limited and cannot be customised in the same way. I understand this will only apply to a very small percentage of users but was a great tool non the less, hopefully someone will be able to recommend a work around other wise we will have to keep the remaining clients on sage much to their disappointment!