Personal climate impact question

An issue likely of little overall impact of itself but could be fairly significant if applied to all future travel situations like this

I’ve committed to not flying unless completely necessary for environmental reasons (see https://​​flightfree.co.uk) as flying can easily overwhelm any other measures to reduce personal carbon footprint

I’m travelling from London to Belfast soon and the non-flying routes are extremely long and will take up a whole day each way (too late to book sleepers which would be more time effective)

Flights cost the same and would free up 2 days. On one of these I could work freelance and earn about £300 after tax.

I’m wondering if I should bite the bullet and fly, work on this day and donate the money to a climate related charity. This generally isn’t my giving philosophy but it would assuage the guilt from flying somewhat in a way that another donation to AMF wouldn’t.

Return flights would release around 0.26tonnes CO2 equivalent, land travel ~25% of this

Issues:

Lack of reliable info on carbon impact of donations unless I just cannot find this—offsetting appears to be very ineffective

Impact of optics ie loss of influence on others to reduce flights if seen to take them

Loss of personal satisfaction at avoiding flying

Any thoughts /​ experience of similar?