Knocking noise after coilover install

Hey guys

Recently had a set of Stance + coilovers installed on my 2016 Ibiza FR and at first i had to drive it a week without shortened drop links on as the first set i bought got “ lost in transit.”

Now everything was fine until i had the drop links installed and now there is a very loud knock/clunk coming from the front, had the garage look at it that installed the coilovers and they said that the gearbox mounts had worn and needed replacing, so took it into SEAT and they are saying the knocking is coming from the coilovers but wouldn’t explain anything more than that and that they can’t work on the car as it’s been modified. Now as there was no noise when the drop links weren’t fitted could the noise be the ARB making contact with something? Possibly the driveshaft?

Just looking for advice or anyone that has had similar problems

Link to Coilovers and drop links https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/142737363442

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/292140899118

Thanks