Bit more info.

The 2 GI lines going to the play field are made up of a 2 pairs of wires: red/white pair and an orange/green pair.

Most lamps, apart from the last in a chain, should have two of each wire in the pair attached. ("Daisy chained")
The coloured wire may be replaced by braid in some sections but it does the same job.

You will have to follow these wires back from the first non working lamp to the last working lamp in the chain and check for good connection of all (4) wires between the two.
You can do this with a continuity checker or just visually by following the coloured wires.

Hope that makes sense.
Good luck.

Edit.
Just re-read original post and because affected lamps all seem to be around the section of braid, that will obviously be good place to start looking.  That braid should have continuity with either the red, white, orange or green wire, depending on which side pair is involved.