Re: Hotpoint Cooker EW91
It will almost cetainly not be ‘original packing’ more likely to be a heat resistant spacer or a liner from inside the timer that is breaking up. The access to the controls on this appliance is not a DIY job, Back panels, side panels and the hob assy plus other bits & bobs need removing. I strongly recommend you have a look at our Repairs@ section via the link in my sig. The timer unit itself is over £100 of a part so you need to handle with extreme care. Unit is around ten or more years old, but is quite a solid job.
Please isolate from mains if you intend to proceed further.