https://triumphherald1360.blogspot.com/2016/01/heater-fanblower.html Sorry about earlier; I was watching the smoke curling up from the grill, typing as fast as I could, and waiting for the smoke alarm to go off. The link above is to Darren Grove's modification on his blog. I bought the smart car blower for £7 off eBay; it's an almost straight fit to the Herald heater body with no cutting required. The only difference is that the vanes are huge and won't fit, so if you want to avoid cut