Sorry for the late update, only just got round to looking at the mini, after 2 garages saying it sounded like bottom end and may require a new engine I left it for the time being and bought another car to run around in. I finally took the plunge today and set the car up on stands, removed the wheel and inner arch cover, as soon as I looked at the belt it looked in poor condition with cracks, however there was also a 20mm section with no rubber at all, this must have been causing the tensioner to knock.Removed the belt and checked all the pulleys, all clear of rubber and not play, fitted a new belt, started the car for 30 secs to settle the belt then checked tension and alignment to the pulleys. All ok, refitted everything back on and idled the car for 5 mins with no knocking, run the car around the block with no noise then went a little further around the town and down the dual carriageway, all seemed good. Wife has taken the car to work this evening and she mentioned that there was no noise, fingers crossed this has corrected the issue. In fairness the noise did sound bottom end but it shows the value of people who know these cars and have experienced these cars, thank you to you all for the advice, it was very much appreciated. Next time I will look at the belt first before the tensioner.Hey lordf I know this is a old post but I have just had a similar knocking from what sounds to be that side, I have changed the tensioner and also changed the oil and filter as a precaution, started up and all was good but after 5 minutes of driving it comes back, I park it back on the drive and turn off, switch back on and the noise is there for a moment then gone again, has anyone else had this issue please.