Hornby 0-4-0 Wheel Dismantling

[PatB]

I've just received a parcel of Hornby Smokey Joe chassis which I hope to form the basis of a budget fleet of narrow-gauge locos.

 

Whilst it seems fairly common to use these chassis as-is, I think the wheels would look better in narrow gauge if I got out the piercing saw and thin out the spokes a bit. The construction of these wheels is such that doing so requires the plastic spoked centre to be removed from the metal rim/back unit for surgery, and replaced/refastened afterwards. Has anyone done this successfully and, if so, are there any tricks to make the process reasonably pain free?