It seems that MOT type 1 is now known as SHW clause 803

Similarly MOT type 3 is SHW clause 805

But I have a requirement for SHW clause 513

I can't find anyone selling an aggregate described as Cl 513, just lots
of specs for road schemes under .gov.uk demanding its use.
it's "permeable backfill to earth retaining structures", what is the
stuff called in old money?

SHW = specification for highways work

Andy Burns wrote:

I have a requirement for SHW clause 513

I think the USA equivalent is AASHTO #57