Clutch slave cylinder disconnect help

Hi all,

I am working on replacing the clutch slave cylinder on my car, I've got the part from Luk and it comes with the slave cylinder itself and the pipe with the quick connector.

I was able to get most the way through the job by following some guides on YouTube (Even though they're listed for Fiat 500s: Fixit Fallows, Fat and Happy kid), both of the guides avoid making use of the quick connector and instead remove the pipe from the new slave cylinder and connect it to the old one, in both of these videos it looks extremely easy to disconnect (simply take the metal clip out and pull the pipe), however mine is visibly corroded and will not budge whatsoever, I have tried everything to get it to move even resorting to cutting away at the plastic housing around the connection. I'm slightly concerned that it is corroded internally and essentially welded together as I've heard the quick connector likes to do also.

Here is a link to the specific bit in question: Youtube.

I'm sure even though the plastic has been damaged I could drive it but I'm out of ideas on how to separate these two.

Does anyone have any ideas?

Many thanks.

(On second thoughts I think where the pipe attaches in the slave cylinder is plastic not metal which makes this even more weird...)