Use a simple household thermostat to control a cabinet fan so it comes on at ~30C or so.
https://www.screwfix.com/p/flomasta-...ermostat/7593g

Or a process controller
https://www.ebay.co.uk/itm/PID-Digit....c100005.m1851

CPC are good place to look for fans - cheaper than Farnell (sister company) or RS. Mains or 12V / 24V
https://cpc.farnell.com/w/c/electron...=fans&aka_re=1