You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Somehow the seatpost clamp has rubbed
and damaged the dropper valve. I can't now attach a pump to increase pressure as the thread is mangled. Any ideas for a fix so I can attach a pump?

A plastic pipe with a clamp you can do really tight , like on a hosepipe . Same on the other end attached to a pump .
It only needs pressuring once or twice a year .
Look like plenty of thread left once you can get it started, I doubt you’d get a Siemens in there, try using a junior hacksaw blade hand held to open the thread back up.
I've got one of these in the toolbox and have had success cleaning and re cutting threads on valves. It 'may' do the job as there does look like plenty of thread left. Just be careful starting off not to X thread it.
Should of been “die”, don’t know how it was autocorrected to Siemens
And if it really is gubbed then you can buy the air cartridge as a spare part
The valve assembly is obviously manufactured separately. Can you get it to unscrew once its depressurised? It looks like there's a couple of slots you could get long nose pliers in.