Folding Bikes - Raleigh Twenty headset

The fork on my R-20 is stiff when you rotate it.
I'm guessing the bearings in the headset needs a little cleaning.
I'm going to buy a headset wrench to remove the headset, and I'm wondering what size?
It's a stock headset.

30 mm or 32mm?

Thanks

I removed mine with an adjustable wrench; It's likely neither of the dimensions you cite as it will be an imperial measurement. I recall buying an old 'all in one' Raleigh spanner hoping it would be a fit and it wasn't. I may in fact have not used a wrench but in fact used my little square jawed vice (not attached to a bench) to fit over the large nut. Which worked fine.

http://washford.scene7.com/is/image/Washford/405449?$prodthumb$

oh maybe bad news

I serviced the head set on my bsa 20. Put the stock headset back on.
The plastic bush at the top was sticking on the fork steerer, and turning in the frame
even though I greased the inside of it.

I could have polished the steerer tube of the forks. So it would move easier.
But have changed the forks on the bike

I very recently pulled mine apart with adjustable wrenches. Came apart easily. Decent quality parts in most of the headset, except for the regrettable nylon bushing.