I'm pretty sure it's not a Wurster, I reckon it's a nice hollow Frank & Reif Panzerkampf Abzeichen. Take a look at this for comparison.
'I do not think we can hope for any better thing now.
We shall stick it out to the end, but we are getting weaker of course, and the end cannot be far.
It seems a pity, but I do not think I can write more. R. SCOTT.
Last Entry - For God's sake look after our people.'
In memory of Capt. Robert Falcon Scott, Edward Wilson, Henry Bowers, Lawrence Oates and Edgar Evans. South Pole Expedition, 30th March 1912.
I agree with Ned, I think Wurster grass was different then the photo you posted.(Even think he organizes the grass in a pattern) But as you, my experience is also limited.
It might be a F&R as I am not familiar with them. I do not believe it is a Wurster.
Here is mine to compare.
Searching for anything relating to, Anton Boos, 934 Stamm. Kp. Pz. Erz. Abt. 7, 3 Kompanie, Panzer-Regiment 2, 16th Panzer-Division (My father)
Ned showed a good comperison badge, but these are not made from F&R, but from FCL. Nice hollow zinc variant.