Thank you all for your responses, I’ll look for the equivalent sellers as I live in the UK.
Before posting this I looked on Toolnut and Ashley Iles as they both sell brass ferrules for chisels but the dimensions don’t quite match up with mine. If I bought some but they were slightly too big how would I pack out the handle to ensure a snug fit?
Also, would I risk damaging the handle if I use the chisels in the meantime whilst the ferrules are split?
Sorry for so many questions.