It is usually not in most people's best interests to give up or transfer guaranteed, defined benefit or safeguarded rights pensions.
For defined benefit schemes you carry no investment market risks - investment markets can rise or fall and it is up to the pension scheme to honour your pension rights irrespective of market performance.
You carry no annuity rate risk as the pension scheme must buy you the guaranteed pension at retirement anyway irrespective of annuity rates.
You carry no inflation risk as the pension must buy you an inflation linked pension anyway irrespective of future inflation.
YOU SHOULD OLD CONSIDER A TRANSFER IF THERE ARE OVERRIDING REASONS TO DO SO THAT OUTWEIGH THE ABOVE SAFEGUARDED/GUARANTEED RIGHTS.