Shock! Horror! (or to paraphrasef Edmund Blackadder - "spherical and plural")
"companies only have a month to reply to requests and face fines of up to 4 per cent of revenues if they don't comply"
Some homework needed here:
[1] the provision is for a calendar month to provide the information or to indicate how long it will take to do so.
[2] There's no way on earth the maximum fine would be levied just for missing the response deadline to a SAR.