Thank you for the reply.
Can I safely rule out that the issue isn't with the toilet itself; ie, it isn't faulty, but rather how it is connected to and the type of flushing system?
I posted this on the Screwfix Community Forum but depsite many views, there were no replies!
My wife is a wheelchair user and we previously had a toilet fixed to a plinth to raise it so she could transfer more easily. We have had it replaced with a comfort toilet which is the same height as the...