This ones a bit cheaper Andy www.ebay.co.uk/itm/394002387339?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&customid=CjwKCAjwopWSBhB6EiwAjxmqDXe6P24u5CYUgihPOzKxFMg3ronf6Ajwa8QcyDbuMrxkNNwCR4HS3BoCtxcQAvD_BwE
A word of warning your exhaust muffler is indoors. These are poorly assembled and leak carbon monoxide plus there's a moisture drain hole in it compounding the issue.