I am not sure you understand what our governments did "over there."
A huge amount of responsibility lies with us for making sure there were terrible governments, corruption, minorities ruling over majorities. We designed all of these places to NOT be successful, in order to own/rule them.
Most countries that we pulled out of ended up in civil war - stoked by us, and, of course, using weapons purchased from us.
We had a divide and rule policy in all countries that we were forced out of.
It seems that most think we were nice, went to these places and helped out a little, then went home after teaching them how to speak English and drink tea.
I'm actually from a former British Protectorate so I know better than most in the UK what the post-colonial landscape looks like.
Interestingly, countries like Qatar were also British Protectorates and in fact Qatar has only been independent since 1971. Yet they've had an entirely peaceful society since then and used their vast resources to benefit all Qatari citizens. Compare and contrast to Nigeria, which also has vast natural resources.
Most countries gained independence in the 50s or 60s. It's not an extremely long time ago, but it's long enough that at some point there needs to be some responsibility taken the countries themselves. The British also didn't cause the massive cultures of corruption that plague for instance many African countries.
It wasn't much longer ago that Germany lay in ruins and look at them now. Yes they had plenty of help rebuilding via Marshall aid but it's not like most former colonies haven't had large amounts of aid from various sources either.
Overall I hate this narrative that only white/colonialists bad and everyone else good/exploited. It's not like the various areas were living in peace, equality and democracy when the colonists showed up. It's a weird sort of racism or fetishism of the "noble savage".
Be all of this as it may, there is I would say almost zero appetite in the UK to fund a scheme like this. We're in a cost of living crises, taxes are high and about to become higher, services are cut to the bone, we already have an aid bill... there is no way the tax paying public would wear this. No chance at all.