anyone know where I can get a longer boom extension for my ancient but still working 1994 neil pryde wave boom?

I can fit a 5.0m sail on the boom but would like to get a 5.5m so need about 10cm more.

The extension in the photo is about 27mm diameter and 46cm long. I need an extention about 56cm long.

I've tried my local shop and they said they would try an order one but I'm not holding my breath on that one.

cheers