Thank you to all that have replied so far, much appreciated.
Since this post I have had some success. I have managed to get a couple of part numbers from Al-Ko International here in Australia. There are two sized nuts, 24mm and 27mm. I just have to determine which size is applicable to my application. There are a couple of ways of doing this, one by measuring the thread on the axle or easier still, taking the part number off a plate that is fixed to the axle from which all associated parts are identifiable.
just as aside, my van is the imported (obviously) English version (for want of a better description), the one that is running around all over the UK and not the specific model built for Australian conditions. As a result there are some differences, for example, drum brakes, shoes, one-shot nuts and many other parts, are imported from England and not readily available here. I was advised when I purchased this van, that I may have difficulty in sourcing parts in Australia. Even the Thetford fridge is the English version and parts unavailable here.
I recently noticed the Panoramic window has developed a crack. Now that's not a cheap fix and obviously a design fault from reading forums with people suffering the same issue.
The distributors of Swift here in Australia are far and few between and carry little stock. Even Swift UK are not very supportive with extremely poor customer service and at times,most unhelpful. Don't get me wrong, I love my van. I have spent a few dollars and hours getting it to where I want. I will however, have to make the decision eventually whether to keep it as if the parts situation continues to be difficult, I may have to let it go.
When Swift vans were first introduced into Australia they at first were very popular. However, over recent years it's popularity has waned basically because they struggle with our harsh environment and build quality. I'm often finding myself reinstalling screws from cupboards that have worked loose and that's keeping to the black top!
Many thanks LJS