It is clear when you filter the Glassdoor results between UK and Singapore, and you note the obvious difference between ratings. Although Singapore has small sample size, it has consistently been rated poorly.
Under current leadership the Singapore Thomsons culture will never be like the vibrant UK office. At best Singapore office is more of a back office support to UK - they help implement global accounts. Singapore office does not generate revenue..and its a cost centre.
While there's been gallant attempts to go the market and showcase Thomsons. Most damaging is that Singapore leadership does not have credibility in the market.