> For reasons outside my area of expertise, UK companies sometimes divide themselves into numerous sub-companies
One of the common reasons for subdividing firms (in general, not particularly the UK) is to take advantage of liability limitations, which work as well for corporation as shareholder as for natural persons as shareholders. If it is less onerous to set up firms in the UK, you'd expect UK firms to do more of this, because the cost/benefit analysis would favor more of the cost is lower.
One of the common reasons for subdividing firms (in general, not particularly the UK) is to take advantage of liability limitations, which work as well for corporation as shareholder as for natural persons as shareholders. If it is less onerous to set up firms in the UK, you'd expect UK firms to do more of this, because the cost/benefit analysis would favor more of the cost is lower.