The standard belongs to the destination
It is natural to assume that a translation bought in Devon is judged by British expectations. For Slovenia it is not. The credential is named plainly at that end: a court-appointed translator, a sodni tolmač. That is a Slovenian status, and buying the translation here does not change whose system defines it. You are, in effect, hiring to somebody else's specification and having it delivered locally.
The language Slovenia requires
Slovenian is the language wanted for documents used in Slovenia, and the record is carried across in full. Because the signer holds a court appointment, the wording tends to stay close and literal rather than helpfully smoothed. An official Slovenian translation in Plymouth is meant to be checkable against the original line by line, which is a different aim from reading nicely.
Certification Slovenia accepts
The finished set carries the translator's signature and date, given under the court appointment that Slovenia issues. Slovenian authorities work from that appointment, so the question of who stands behind the text is answered on the page itself. If the body receiving it also wants notarisation, that can be arranged alongside; it is an addition to the certification rather than a substitute for it.
Per-page cost and turnaround
Pricing is £25 for each page of the record, and the standard wait is 2–4 business days from a clear image, shortening to 24–48 hours where the express route is taken. Neither figure shifts because the signer is court-appointed. The appointment governs who may sign the Slovenian, not how quickly the pages can be written or what each of them costs.