TESSAs - any withdrawal of capital before the end of tax term will entail loss of tax free status. Interest can be withdrawn without affecting tax free status. Maximum interest .which can be withdrawn without losing the tax breaks is the 'net' amount i.e. the amount you would have received if the account had not been tax free.
Equity in house - in the event of the main residence being sold and the mortgage being repaid, there should not be any tax implications concerning the splitting of the equity. Any sale of second homes will entail capital gains tax considerations.
Endowment mortgage - life policy may be rewritten on single life basis or assigned to sole owner which will have qualifying consequences. Surrender where policy non-qualifying will have implications for higher rate tax payer or policyholder who are taken into higher rate by surrender.
Where one spouse remains but the other spouse pays the mortgage, then the payer may claim MIRAS, even though the house is no longer that individual's principal private residence.
PEPs - will, of course, be individually owned. If these are sold to realise cash, then there will be no income of capital gain tax consequence, but the benefit of the tax free regime will be lost for the future.
Shares/Unit trusts - any realisation for cash will have Capital Gains Tax implications.
Single Premium Investment Bonds - any withdrawals or encashments should take into account chargeable event rules and possible liability to higher rate tax. With Profit Bonds may incur a market value adjuster on early encashment.
References to taxation and legislation are based on our current understanding of their application. Legislation and taxation are liable to change in the future.