We had some temporary plumbing done for connecting up a washing machine. However, when I now come to install the washing machine I find that the waste pipe to connect up to looks like 18-20mm plastic pipe and I don't know how to connect this to the waste pipe from the machine as this would typically go into a stand pipe. The current plumbing runs across our kitchen (behind cabinets) to our sink waste. This is only in place for about 6 months while an extension is built. Any suggestions on how I connect the waste pipe to the 18mm plastic pipe? Is this an ok temporary setup or are we likely to have problems? Would we be better off swapping this with the dishwasher which has more regular plumbing? Slightly worried that it won't be able to cope with the amount of water used by the washing machine.