Keith - for illustration purposes only - this is the type.

http://www.screwfix.com/p/reversible-gear-puller-2-3-leg-100mm/48634

Note that you need one big enough to grip the boss. I took my wheel off and put the three legs under the edge of the boss rim where the steering wheel fits. No need to remove the cowl..
Take the centre nut off and it will come away easily. The problem I have with my puller is that it's a bit oversize - not bought for steering wheels, so I really need two pairs of hands to hold everything in place while I turn the centre nut.

DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4