Aaah, we're back online now. Spent half an hour writing an in-depth response this morning only to lose it all as the site was being backed up when I clicked send!!!
Anyway, thanks for your help so far and to cut that long email short I currently have 2 options.
1) I have already imported the external forms database into a second table on the entry/main database and explored that option.
2) I have another database process that was setup in the same way and I print the forms in the following way:
A script asks you which order you wish to collect information from (i.e. collects all the lines of the respective order) and presents that information on the required form.
I prefer the second as it only requires one table and therefore simplifies the process as I have other external databases that have to be added (as tables) shortly with contacts, product information, etc. My only issue is that any information pertaining to that order realistically needs to be duplicated accross all lines in that order. This creates another problem of copying and pasting data from numerous fields across multiple records/lines of an order.
Thanks for your help