So this took a little longer to sort than I'd have liked, given the cost of the chair etc. You have to submit the request through the internet, so there's a delay in getting a response. Once I did get one the representative I spoke to ended up going around in circles for a few days asking for the same details over and over again, which was a little frustrating. Eventually got someone else to help though and they had it solved the same day.
Parts take about 2 weeks to arrive. To stop your warranty being voided you have to let an "engineer" visit to undo a couple of bolts and fit the new one
. Found that quite funny but at least it will be sorted, likely not until the end of November though.