Hi,
It certainly looks like Altro!
Ultrapac Renovate, scrub using standard speed rotary using brush, suck up slurry using a decent wet and dry, repeat 2 or 3 times if really bad. If client complains that the floor is still not acceptable, inform him that any damage has been caused by improper maintenance.
As phil has stated, previous cleaners have probably tried allsorts before you!
As Martin has mentioned, any sort of polish is a no no.
Very unlikely to cause damage with a black pad, (but you really should know better!), unless, of course the floor was already damaged, such as a loose seam, or tear in the vinyl.
Depending on location and footfall, damp mop with nuetral cleanser daily, scrub as often as needed to keep up the desired appearance.
Regards,
Rob