Manfrotto 190CXPRO3 with stuck 128RC head (1 Viewer)

My Manfrotto 128RC head is stuck on my Manfrotto 190CXPRO3 tripod. I bought them separately some years ago, and they get a fair amount of use, both for my birding telescope and for video. And I've had them apart some years ago.
I've unscrewed the 3 retaining worm screws under the tripod attachment plate, but the 128RC is well and truly stuck. I've gone as far as hitting it with a rubber mallet, but the head remains stuck. I was hoping to try a more advanced video head with "fluid" properties, but that now seems impossible. (The tripod and head are way too large to go in the freezer area of my fridge, and I don't now have a chest freezer if that would have helped.) So far, I've not tried any form of penetrating oil.

Any ideas? and thanks in advance... otherwise, the 190CXPRO3 is probably my favourite tripod

Lol, there's a big thread on this one. Check it out! I have 2 Manfrottos and no problems since I read it. It will work out.

190CX3 is my fav too!

I've had stuck heads before. I seem to remember wrapping a face flannel round it, and either putting it in a vice or using a pipe wrench to shift it. If you give it a blast of WD-40 or silicone spray first it may help.
I remember a carpenter telling me that before undoing a stuck screw, they tightened it some more first, which apparently is enough to break whatever is stopping it unscrewing. I wouldn't hit it too much!