---
title: "89 CASTELNAU RTM COMPANY LTD — Ownership Dossier"
canonical: https://whiteintel.dev/entity/db258740-52fe-55b2-8778-07cb02db3d79
json: https://whiteintel.dev/api/public/dossier/db258740-52fe-55b2-8778-07cb02db3d79
identifier: oo:GB-COH-07190205
jurisdiction: GB
risk: Low
source: WhiteIntel corporate-ownership graph
---

# 89 CASTELNAU RTM COMPANY LTD

**Type:** Company  
**Jurisdiction:** [GB](https://whiteintel.dev/jurisdictions/gb)  
**Identifier:** `oo:GB-COH-07190205`  
**Risk level:** Low  
**Canonical dossier:** https://whiteintel.dev/entity/db258740-52fe-55b2-8778-07cb02db3d79  
**Structured JSON / MCP:** https://whiteintel.dev/api/public/dossier/db258740-52fe-55b2-8778-07cb02db3d79  

## Ownership & control

### Owners / controllers

- **Mr Hans Jurgen Blanckenburg** (beneficial owner) — 50% — https://whiteintel.dev/entity/b3462605-6269-5079-8f42-8d12612bd4c2
- **Mr Hans Jurgen Blanckenburg** (beneficial owner) — 37.5% — https://whiteintel.dev/entity/6d652ef0-1c19-4fef-9e4c-0b79d2baed55

### UBO chain (walk to the ultimate owner)

A **2-step** ownership/control chain to the ultimate beneficial owner is resolved for this entity. The full cited chain unlocks with a paid API key or a one-off dossier — https://whiteintel.dev/pricing.

## Company profile (live · UK Companies House)

- **Company number:** `07190205`
- **Status:** active
- **Type:** private limited guarant nsc
- **Incorporated:** 2010-03-16
- **Registered office:** Bray Lawn, Fishery Road, Maidenhead, Berkshire, SL6 1UP
- **SIC:** 68320

### Officers

- BLANCKENBURG, Karen Gillian — secretary · appointed 2024-09-05
- BLANCKENBURG, Hans Jurgen — director · German · appointed 2010-03-16
- BLANCKENBURG, Karen Gillian — director · British · appointed 2025-10-02
- HIGHET, Catherine — secretary · appointed 2010-03-16 · resigned 2025-07-16
- HIGHET, Catherine — director · British · appointed 2010-03-16 · resigned 2025-10-02

### Beneficial owners (Persons with Significant Control)

- Mr Hans Jurgen Blanckenburg — 25–50% shares · individual PSC · England — since 2017-03-15

## Provenance

- OpenOwnership — https://find-and-update.company-information.service.gov.uk/company/07190205
- companies_house_bulk — https://find-and-update.company-information.service.gov.uk/company/07190205

---

_This is the markdown-for-agents view of the WhiteIntel dossier for **89 CASTELNAU RTM COMPANY LTD**. Human view: https://whiteintel.dev/entity/db258740-52fe-55b2-8778-07cb02db3d79 · Structured JSON: https://whiteintel.dev/api/public/dossier/db258740-52fe-55b2-8778-07cb02db3d79._

_Risk levels are heuristic investigative leads, not legal determinations of beneficial ownership. Every claim carries a source; an absent edge means "not yet observed in current sources", not "does not exist"._