Time was passing I was busy with life and eventually I managed to fill it in today, submit it and pay. Gave referee details as on the signed documents from last year.
However I became worried if they will accept referee forms signed autumn last year? It will feel awkward to ask referees to sign again

I searched the forum and some people claim that documents cannot be older than 28-30 days from the application date. However I'm unable to find this requirement in any of the UKVI documents or maybe I'm not looking in the right places?
Can someone put me out of my misery?