Johnny B Good wrote:

Oddly, they all look like figures typical for long life / rough service
lamps rather than for the UK standard 1000 hour life GLS lamp.

The spec sheet says 1000 hours, and avoids use of the word "rough" but
does include words such as "robust", "industrial" and "reinforced".

http://www.cromptonlamps.com/images/pdf/trad_sp_pro_range_gls.pdf