Can anyone identify this larva?

Does anyone know what this larva is? Is it garden friendly or unfriendly?

 

How big is it, where did you find it etc.

 

About one centimetre long. Crawling on the patio wall. There have been a lot of these teardrop shaped pupae that turn brown, attached to the patio walls and other walls. I am guessing this larva could be from the same insect as the pupae. Hoverfly?

Also, today I was trying a couple of things to try to deter ants that are coming in, one was spraying dilute vinegar on the wall, so I hope that if this larva is a beneficial insect that the vinegar isn't bothering it. So many of these remedies are two edged swords.

 

Well, not something I'm good at IDing insects but I'm sure someone else would have an idea.

Hoverfly sounds possible, have you got any standing water around anywhere, I sometimes see those rat tail maggots that turn into hoverflies.

 

Yes it has been raining and I have buckets of collected rainwater for watering plants.