Self-Referencing Within RDF Files

Question

I'm trying to load an RDF file into webvowl but am unable to see the relationships between resources as they are all "External". My understanding is that this is due to how I'm referencing the resources in the file (something I have not done before). In terms of my use case, I'm writing a turtle file of RDF triples describing concrete (instantiated) resources - specifically, using the DCAT ontology to describe the structure of an API.

When I look at ontologies such as DCAT I can see that they use a hash to separate the ontology and resource id, e.g. http://www.w3.org/ns/dcat#byteSize. In contrast, the code generator I'm using to write the Turtle file uses a forward slash to separate the ontology and resource id, e.g. http://example.com/dataservices/{id}.

I've tried various combinations of slashes/hashes, and including/excluding file extensions to no avail. Any advice on how to properly self-reference these ids would be much appreciated. An example of the resource relationships I'm trying to visualise is shown below, the raw file can be found here, and the (currently invalid) visualisation is here.

@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dct: <http://purl.org/dc/terms/> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/catalog-1> a dcat:Catalog ;
    dct:title "An Elexon dataset catalog"@en ;
    dcat:dataset <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/3519b2019120f09555a5e6b13de5e6ee405eb963>,
        <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/9e48ef6df2c415e78e2504f36a86054092434808>,
        <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/b63ddc4ec45655718cb8e29e9f05c312c360a127> ;
    dcat:service <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/c002eba1b6e86da2257235ff784433e06fc49ddf> .


<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/4107792ac75242bc833c888052ebef1f1e688ef7> a dcat:Distribution ;
    dcat:accessService <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/c002eba1b6e86da2257235ff784433e06fc49ddf> ;
    dcat:downloadURL <https://api.bmreports.com/BMRS/B0610/v1> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/53539e5e45daf8989e3b08f0aec6431a50a34aa2> a dcat:Distribution ;
    dcat:accessService <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/c002eba1b6e86da2257235ff784433e06fc49ddf> ;
    dcat:downloadURL <https://api.bmreports.com/BMRS/B0620/v1> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/ec0dcc1fe3d8ad6ba208b0a9a892a3f96dc6c12d> a dcat:Distribution ;
    dcat:accessService <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/c002eba1b6e86da2257235ff784433e06fc49ddf> ;
    dcat:downloadURL <https://api.bmreports.com/BMRS/B0630/v1> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/9e48ef6df2c415e78e2504f36a86054092434808> a dcat:Dataset ;
    dct:description "Actual Total Load per Bidding Zone"@en ;
    dct:title "B0610"@en ;
    dcat:distribution <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/4107792ac75242bc833c888052ebef1f1e688ef7> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/b63ddc4ec45655718cb8e29e9f05c312c360a127> a dcat:Dataset ;
    dct:description "Day-Ahead Total Load Forecast per Bidding Zone"@en ;
    dct:title "B0620"@en ;
    dcat:distribution <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/53539e5e45daf8989e3b08f0aec6431a50a34aa2> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/3519b2019120f09555a5e6b13de5e6ee405eb963> a dcat:Dataset ;
    dct:description "Week-Ahead Total Load Forecast per Bidding Zone"@en ;
    dct:title "B0630"@en ;
    dcat:distribution <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/ec0dcc1fe3d8ad6ba208b0a9a892a3f96dc6c12d> .

<https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.ttl/c002eba1b6e86da2257235ff784433e06fc49ddf> a dcat:DataService ;
    dct:description "API for the Elexon Balancing Mechanism Reporting Service"@en ;
    dct:title "BMRS API"@en ;
    dcat:endpointDescription <https://raw.githubusercontent.com/OSUKED/ElexonDataPortal/master/data/BMRS_API.yaml> ;
    dcat:endpointURL <https://api.bmreports.com> .