Hi Zag.
With regard to life assurance, there is nothing to stop your estate benefitting from the full value of your personal life assurance and any policy associated with your mortgage. There may be inheritance tax issues for your dependents, but that is a separate matter.
With regard to life assurance provided by your employer, the amount of beneift that can be taken as cash is capped at four times salary. The remainder of the policy value must be taken as a pension/annuity, which will be treated as income for tax purposes (i.e. your dependents will pay tax at their marginal rate).
So in theory, you are not prevented from having 'too much' life assurance, other than the tax issues surrounding the life assurance provided by your employer. Having said that, most underwriters would impose a limit on the amount of cover you can actually have in place, so actually getting cover could be the problem, or it will be capped.
The limit to the amount of pension you can receive from company scheme is 2/3 of salary. Any excess must be returned to the company, or is taxable if taken by the employee.
Their are no such restrictions on personal pensions or PRSAs, but the amount of tax relief on your contributions is capped at various limits depending on your age.
I'm no expert on pensions, so the last two paragraphs may have a couple of holes in them, but I haven't the time or energy to fill them in!
Hope this answers your question.