UK economic fluctuations effect charity incomes, voluntary ones first – though not seen straight away, analysis showsAverage charity income growth will slow or become static in downturn, though actual average incomes won’t fall, experts predict“Don’t accept or expect defeat”; but be cautious and “ensure resilience against income volatility”, think tank urgesGrowth in charities’ average voluntary income rises or falls 10 months after any rise or fall in GDP growth, followed by peak impact on overal