Richard,
BIG-IP which your IT department is using is a hardware device.
For your testing you can use BIG-IP Virtual Edition (VE) - it is a VMWare Virtual Machine - download it from www.f5.com/trial/
VE will rin in VMWare Workstation on your XP machine. There are plenty of articles on devcentral.f5.com helping you to work with VE (it is not trivial if you have never worked with virtual machines and networks). Once you install the VE and license it correctly you can then use it as if it was a hardware BIG-IP box so you can run iControl SOAP queries against it .
The only limitation of VE is that its network throughput is capped at 1Mbis/s (which is fine for your testing) and the trial license will expire after 90 days (hopefully that is enough to get your scripts up & running).
Sam