Coffee Appreciation

I have a gaggia baby 06 class d.
I bought it from vince of this parish and its been absolutely brilliant, a real bargain, probably the best money I've spent on anything.

I look after it and run pullycaf through it once a month.
Recently the steam has went a bit funny. Previously it had good pressure and came through in a nice constant jet with no spluttering.
It's now started to splutter a lot, it quickly alternates between invisible jets of steam to sudden bursts of white visible steam at the nozzle with some small splashes of water.
It no longer gives usable steamed milk.

I ordered a new steam thermostat hoping that was the issue but it hasn't fixed it.

Any one have any ideas of anything else to try that doesn't cost too much?
I'm worried that it's the pump that's fucked or some other expensive part.

I'll post a video of the steam action later when I'm home.
Would really like to get another few years out it but things like the pump might not be economical to replace