Astonish is marvellous - its a paste cleaner & Wilko's used to sell it but my one doesn't anymore. home&bargain sell it tho. Its mildly abrasive so if your cooker top is ceramic then so careful but it hasn't ruined mine & I've been using it for four years.
Dont you ever watch " how clean is your house"!!!! aggie and kim had a great way of cleaning the top of a cooker.... simply get a dishcloth, soak it in hot soapy water, pop the cloth on the top of the cooker ,leave for 10mins and hey presto!!!!!!!! hope this works for you!!!
I do watch that peachy!! I used one of their tips, to use biological washing powder, but it hasn't worked! It's just a thin layer of grease I assume, in patches, obviously been there ages, and now can't shift it!