Thaddy - It was definitely Delphi 2, as I still have the original disk. I never owned Delphi 1. But I am sure you will be right that the limitation was for Delphi 1. My program started off on an Apple ll, then moved to the IBM PC using Turbo Pascal and a graphics package. In those days all memory was so short that you had to use every trick in the book to economise.
Iainz - Thank you for the kind suggestion. I am very willing to share my program and data with anyone. But frankly the source code is in such a mess its in no fit state at the moment. I started to rewrite in Delphi 7 (free disk with a magazine) on a Windows 8 machine, but found that Delphi 7 had problems with Windows 8. The program itself is of little value - very unsophisticated in today's terms. Its strength is in the accumulation of old data that I have, but that is also a weakness as it is all typed in manually. These days modern programs have access to massive amounts of data - its just that they don't do what I want to do.