Are the Newton fellowships (UK) prestigious enough to warrant low post-doc pay? I'm nearing the end of my graduate studies (1-1.5yrs remain) and have been looking out for post-doc opportunities. I came across the Newton Fellowships, which provide funding for up to 2 years of research work at any participating university in the UK. 

The fellowship requirements seem very competitive — a full fledged project proposal and multiple independent evaluations of the said proposal, in addition to the usual requirements. However, in the end, the pay is about 24k £. They do have an 8k £ allowance for research related expenses, but that probably is reserved for publication costs, travel, computer equipment and not a personal allowance. 

From my research into pay scales in the UK, the lower end of the post-doc pay scale begins at about 28-29k £. More over, there is no cost of living adjustments, so if you're in an expensive place like Oxford or London, it's definitely not sufficient.

This brings me to the question — is the fellowship prestigious enough to warrant the low pay? Does anyone have experience with this fellowship (past fellows)? Are there opportunities to supplement the income? Don't get me wrong here... I'm not in it just for the money. Like every academic, the research topic is more important for me. But at the same time, I do not want to be working for well below what's normal and have to severely pinch pockets to support a family.
Where did you get your idea that the lower end of the post-doc pay scale starts at 28 - 29k? Most sources I've seen gives 28-29 the average pay in 2010 and 2011, and the low end near 23 - 24. (High end 35). The numbers are a bit field specific (biology tend to be around 25 - 29 for first postdocs) so I don't know whether the national average applies. 
According to the UCL webpage the Newton is tax free. Your stipend would fall into the 20% band were it taxable, so you should compare it to a roughly 30K starting salary for normal PostDocs. 
At effectively 30K, the pay is extremely competitive for early career (read first time postdoctoral position) holders, provided you don't live in London. (Oxford is not that bad.) London allowance is usually worth around 3 - 4k, so if you live in London your pay would be comparable to the lower-end of a reasonable post-doc salary (with London allowance included).