UK is done for, what makes you say that Bangladesh is as well?
Nothing wrong with 6%+ GDP growth rate per year.
When you are at the absolute bottom your growth will always initially be faster. But then it will hit a plateau.
UK has actually managed to recover from 2 world wars. Has a proud history of facing adversity.
While Bengladesh has achieved absolutely nothing worthy of world praise. Except a very large population in a very small land area. A very low collective IQ does not offer much hope either.
Both nations look bleak. But I'll place my bets on one that has actually done well in the past and present.