Hi Gavin,
You will struggle with that set up the twin motor machine looks good on paper however in reality it will lack the power to do a good job. Carpet cleaning is a little more complex than using a "carpet detergent" as there are many different fibre types, with a wealth of different characteristics which all have there own issues and problems. The first thing to do is get some training, this may sound overkill but it will show you what you really need to get going and how to go about it in the most effective and safe way. Prochem are a good place to start, however there is Alltec, Ashbys and Cleansmart. Many of the questions you will have, have also been asked here many times before so if you use the search bar you can find out alot of the answers.