Some important things dgh853 might have forgot to mention.
In his defense he likely knew all of this.
This is what you'll need:
1. An IXXAT CAN-USB compact adaptor v1.5 (v1.01.0087.10100) or v1.6 - approx USD300 but you may find it cheaper on eBay or borrow/rent it from another forum member or dealer
You cannot buy these anymore, you must get them off ebay or part of a $900 kit (presuming they still sell the kit). You cannot use a new version of the IXXAT CAN-USB either as it will not work with an unlicensed copy of the software mentioned in #3. And to get a license you have to own a business.
3. Sevcon DVT Customer software - free, if you're willing to use one of the older versions such as 1.03c (Google is your friend, as is Dropbox in this case)
Again it has to be version 1.03c or lower and good luck saving your DCF files with it. You need to write down your settings before making big changes. Even if you bought the new version and got a license you would have to use a NEW IXXAT USB-CAN as the old one isn't compatible.
The Sevcon software will run on Windows XP, 7 and 8. There are manuals and getting started guides on the Internet (Google again) on how to use the DVT software including one at https://www.thunderstruck-ev.com/images/DVT%20Tutorial.pdf.
dgh853 is reluctant to link any dropbox files as they have been removed multiple times in the past. These things are more rare than gold at the end of a rainbow it seems. One of the dropbox links you will find will have at least 3 different versions. If you install any new versions completely remove everything from the previous versions. If you find the program wont start up and it isn't 1.02 then install a "merge" installation of TCL and it should work.
Also worth noting. You can brick your sevcon temporarily by making changes. It would be nice to have a backup but these online versions of "free" sevcon software all have issues with saving. I have tested 1.00 1.01 1.02 (which never ran) and 1.03c so far. If you brick your device you will need someone to give you a DCF file to return your device to working order. But good luck getting it from a form member who doesn't work for a dealer as stated it is next to impossible to export the file.
The bonus of course is the ability to control a lot of different things. That said I wouldn't suggest asking "how do I change this" on the forums, get the 200 page DVT / SEVCON GEN 4 manual from the manufactures webpage and read it a couple times. You really need to understand what you are doing when you start to make changes. This isn't a toy you are going to be remotely piloting, it is a vehicle you are risking your life on