The Crossword Centre - Checkerboard Challenge By Arcadia

[Matakari]

Good evening, I would appreciate confirmation for the following, thanks!

GRID A – definitions only

12a Miners' truck (4) : ?RAM  ( TRAM )
15a Lapp guides (4) : ?ILE
5d SI unit of potential difference (8): VOL??AMI  ( VOLFRAMI ) 

One definition is an abbreviation. One answer is the name of a UK company. Each set of across and down clues contains an extra word, relevant to the final step.

[Lie-in King]

Tram - looks ok

Sorry, I've neither the will nor the energy for the puzzle, but if anyone else wants to help, the PDF is here -

http://www.crossword.org.uk/checkerboard).pdf

[JJ109]

5d Matakari if you look at the grid the answer only has 4 letters and (8) is an error. The answer is obviously VOLT

[JJ109]

Also Lapp guides is 15d = Sami (the last 4 letters for what you had for 5d

ie that column should read VOLT---SAMI, but relates to 2 separate clues

SILE is 15a

[Lie-in King]

Well done JJ - I took one look at the puzzle, saw the (8) @ 5d was as shown & left it well alone.  Not my idea of fun at all.

[Matakari]

Thanks, jj109 and Lie-in King, got Grid A all sorted out and having a look at the rest for my pleasure!