Christian - thanks for posting this.

I had exactly the same issue and this helped me confirm suspicions that I needed to re-rivet.

I luckily already had a 'Tackwise' riveter which did up to 6.4mm rivets.

I bought these and used the 6 x 20mm rivets. You need to make sure the X5 bushes are properly aligned so that the 20mm goes through the thinner part of the rubber bushing and out the back.

https://www.amazon.co.uk/dp/B0B2ZVB76W?psc...ct_details

I also found these two made drilling the holes a breeze:

https://www.amazon.co.uk/dp/B081QJ9YM9?psc...ct_details

https://www.amazon.co.uk/dp/B09TDTBRSB?ref...s&th=1

Colalowe - I had the same problem with the bush sticking in the tool on the first bush. So I used one of the bush washers above the plate on the remaining 3 and had no issue.