The reason we dont sell them is 99.9% of the time that isn't the problem and it would cause us pain with daft low value returns.
Yes, we have that clip if you are certain that is all you need.
However, the usual cause of what you describe is normally when the surrounding plastic inside, by that clip, has cracked, it flexes during use, the crack opens, and the handle comes out during use. This is usually caused by either simple old age, the machine being carried by the top handle (rather than the carry slot in the cable rewind) over time or sometimes a fall.
In that case, the usual and most expedient fix is a replacement full back body which can simply be swapped by anyone without tools. We normally supply a good used one for £40 inc UK delivery (assuming blue), but can order in new ones too.