What is this grub?

A friend of mine is having problems in her garden and is wondering what might be causing it.  I have attached a few photos to see if anyone can help. 

Her plants are growing but starting to wilt and go yellow, including weeds like buttercups.  She thinks her neighbour might be spraying weedkiller over his side of the fence and it is ruining her garden, but some of these plants are a good metre or two away from the fence, so she is not too sure if that is what it is. 

She also doesn't know what the grub is in the picture and wonders whether this might be a pest causing the problems.  So before she goes to war with her neighbour over weedkiller, she wants to rule out that something else might be attacking her garden. 

Any advice? 

It's not wise to start a row with the neighbour at all, especially, if you cannot prove your point.

1st picture: could easily be frost damage
2nd picture: bulbs simply die back at this time of the year, it's normal for narcissi to look like this nowish. Buttercup under, most resembles some virus
3rd picture: donno, can be frost damage all the same(what is this plant? if what I'm thinking of, can't recall the name right now, def frost damage)

Saying all that, if weed killer was carelessly used (can be found out without a row), it would exactly land a few metres away from your fence.

I don't think anyone could say conclusively that weed-killer was the cause in any of the photos. I have some sweet Williams over-wintered and they looked similar to photo 1.... caused by lack of water.

The grub looks very similar to a leather-jacket as has been said.

Go easy with the neighbours.

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Our cat arrived home very poorly having wandered along the shared track at the end of the garden. Neighbour had used weed killer... vet said conjunctivitis - But I'm pretty sure it was wandering through newly applied weed killer - we didn't know about it at the time or we would have kept the cat indoors for the evening... not worth falling out with a neighbour over... I may mention it and ask if they could let me know before they spray so the cat can be kept in.

I was not thinking geranium, but still can be frost damage. The commonest culprit right now, even much further south.

Secondary weed killer damage commonly presents itself as distorted growth. We don't see any of that here.

I am not saying, you can rule that out, but that it seems unlikely.