Luke the others have said, we normally just request new ones rather than repair or recondition uniform.
The modern uniform we are issued with is so cheap and nasty, that I’d be fairly confident in saying that you will not be the only one with this issue.
That said, I get your reluctance to wear it at the Sqn. Have a look at eBay for new and nearly new shirts. I’d imagine that you’ll be able to pick up a shirt for almost the same price as a pack of dye.
Also worth bearing in mind that dark blue (No. 2C) shirts will be end of line soon, as the RAF, RN, and SCC have all stopped using them. If you take other ATC-only items, like cap badges, brassards, sqn number badges, etc, as examples then the future isn’t bright for working blue shirts.
Most of the old fixed voice landlines are being disconnected whenever there’s an IT upgrade, office renovation, etc: meaning you have to rely on Skype for incoming voice calls. The problem then is that the Skype numbers are individually assigned and so the number changes with the post holder.