I stumbled across a version of OpenOffice called 'OxygenOffice Professional', the good news is that...
Quote:
“The current version is able to run VBA (Visual Basic for Applications) from Excel documents in Calc (under development) and also you can import Office Open XML (Microsoft Office 2007), Works, WordPerfect files and T602 documents also you can import WordPerfect Graphics graphical files too.”
The bad news is that although it will open Grahams .xls files it wont execute the macro successfully, it comes up with a runtime error. However as the quote says above it's under development and maybe an update in the future will fix this.
For those interested in this programme you can download for free
here