Cloud streets are seldom recognised from the ground because of the scale of them. They were only seen as a distinct cloud form in satellite photos, and as far as I know, that is the only way to positively recognise them. From the ground it just looks like a sky of cumulus, some taller than others.Here's a very similar photo and meteorologist Paul Douglas calls them cloud streets:
View attachment 16448
From here: http://www.startribune.com/mother-s-day-miracle-80s-return-monday-tuesday-strong-t-storms-by-late-week/151113545/
Both in this and in the photo we have discussed, I noticed the cylindrical roll-like shapes. Does altocumulus undulatus have such forms? In Mick's photos, they are not cylindrical but look flatter and irregularly shaped.
Those (again) are altocumulus undulatus. They are fairly obviouslt aligned perpendicular to the wind direction. There is a layer of other cloud below - cumulus fractus - so that perspective give you the clue that the altocumulus is much higher.
Typically, altocumulus, being a "middle cloud" is somewhere in the range of 7,000 to 24,000 (roughly). Once you recognise the cloud type, you have a bit of an idea on the height. In Christine's photo, I reckon the ac is at about 12,000 feet.