Spectator 2580 Cobbled Together

[johnpiper]

I am rather bamboozled with this puzzle and am wondering if i have interpreted the rubric correctly. I have solved all the clued clues. Does the read round the perimeter begin at the end of 26 across and i think that that square is an H? but then i have the third letter of the perimeter clues as a K?
Are 12A and 28A paired and is 28Across wrongly shown as 4 letters in the grid when it should be 5? hence pairing with 12?

A clue for the theme rather than the titled cobbled together would be welcome

[jazzgirl]

The perimeter begins at 20 and goes clockwise.
12a and 28a are a pair. 12a has to be pluralized

[jazzgirl]

Cobbled (street) hint

[johnpiper]

Apologies for being dense so the square with 20 in it which in fact starts S? I see.....in the downloadable grid 28 across only has 4 letters but i think it needs to have 5 to pair with 12 A in the plural!
if you see what I mean
thanks for any further clarification

[jazzgirl]

20 begins with S
Add s to 12a

[jazzgirl]

First word of the pair is 28

[johnpiper]

Gotcha thank you
and your hint works well at 21A!

[jazzgirl]

It looks like you are now well on the way :)

[johnpiper]

actually if 28A is the first wword of the pair then i am none the wiser.

[johnpiper]

I have ROY?

[jazzgirl]

28a normally has an apostrophe which you can ignore

[johnpiper]

Getting there but there are a lot of connections and i am still slogging away