There is a slight risk involved with re-setting the overload thermostat in the manner suggested.
This is a safety device to prevent fire if the cycling thermostat fails to cut out and the air passing over the element rises above 130 degrees centigrade (green spot, for this model). There is a reason why the cycling stat has failed to cut out and re-setting the safety stat (or even replacing it with the correct kit of parts) is only fixing the symptom and not the cause.
There are a number of reasons the safety stat may have opened.
A competent repairman will not just replace the part, take the money and get on his way. He will ask the customer questions to try and establish the cause. He will then carry out tests on various functions and assess the overall condition of the machine to see if other problems are imminent and help you decide whether it is worth spending money on the repair at all. Only when he has done all he can to check for the cause of the problem and the viability of repair will he rectify the cause and then fit the new parts and test. It will usually only take a few more minutes to do all this because these things are second nature to him. (Apologies to my female colleagues for assuming the repair person's gender there.)
The safety stat (thermal overload cut-out) is vital protection against fire. That is why you can't buy it on its own without the associated cycling stat. (I know, you thought they were just profiteering, but not in this case.) If you bang it on the floor, you just might fracture the hard plastic casing of it, leading it to fail to operate when it is supposed to. There are gentler ways to reset it but I'm not telling because you should never do it unless you know for certain that the cycling stat is not faulty. (The fact that it has continuity through it does not mean it is not faulty, the contacts may have welded or be faulty in other ways only apparent after you break it open to see inside.)
If you search the internet, you will find several references to house fires caused by faulty electrical appliances. I don't know how far the investigators go with their investigations but would they be able to tell what happened within the tumble dryer from the incinerated remains?
Mike tsd, April 2013