Neil,
i would wait and see how this year pans out, and if the credit crunch does not affect you, then go for an upgrade,
CM.
Some TM's are set up to dump water into the waste tank, my mate has a blazer and he had his dumping moved from the waste tank to the clean tank, only problem is when dumping hot water back into the clean tank it can cause the machine to over heat.
the alltec cobats dumps back into the header tank if you water gets too hot, this makes it easier for the water to heat up. Personally its a better idea as it means you get very hot water if required.
Open day at HM are supposed to be excellent. Alltec also have theirs too. I would go to both and make your pick. I know I said the blazer was an option, but when it comes to service both Alltec and HM beat prochem on service.
And secondly if you are having a TM, consider a large van, and get LPG conversion. It will cost more for the TM, but the fuel savings is worth make. Make sure you have a LPG garage near you.