"Its employees are predominantly from Northern Ireland (so not British)"

Harland and Wolff once employed more than 30,000 people and led the world in the production of cruise liners.

But it now employs just over 120, so it's demise is unfortunate for the remaining employees but hardly a major catastrophe that some would like to paint it. It also needs to be said that the The 22,000-tonne Anvil Point was the last vessel launched from the shipyard 16 years agoCanberra the last cruise liner was launched in 1960

"The Northern Irish are British, both politically and geographically.
This if true would suggest reunification is unlikely in the immediate future.

As for the assertion the company is/was British Mt Wolfe was a German!