I get annoyed when people do what you did here op. The annoyance is the word "tiny" because it tells me you have made your mind up already.
Now I grew up in Denmark. From Google
Average burden: The average worker pays a substantial portion of their income in total taxes, often averaging around 45% when combining state and municipal dues.
I am willing to pay that in taxes if I was to get something closer to what they receive in Denmark. For example similar maternity and paternity leave, better education, you get paid to go to university. A better welfare system, better roads.
This I would be willing pay more toward. I am not happy to make a voluntary payment to the current system in the UK. And that is what your link is suggesting.
While I would be ok to pay more in taxes I would want a serious overhaul of the current system before this was to happen.
And note I say I am willing noone is "happy" to pay taxes. I am certainly not happy to voluntary pay more into the system we have now as I know it will not go to areas that will make a difference more likely to another Boris type party.
With an overhaul and some heavy reform into the welfare system yes I would be willing to pay more in taxes. As it stands right now. No I am not willing.