to be honest i dont think that is to bad a request what they are asking, they could go even more over board and ask for all kinds of method/risk assessment, then certain qaulifications and also certificates. People think that because they clean windows they are exempt from H+S, were not, we are treated the same way as any other workman on a site
the more notice you take of H+S then the more it gets easier as you will be working in the safest manner pssible and when you go for a tender or a job then when you mention it all it will just roll off your tongue and sound very impressive