This invested directly in the shares of blue chip companies - including ICI, British Gas, Thames Water, United Biscuits and Dalgety - rather than in equity-based unit or investment trusts.
Invesco recently told Mr Coxall, a semi-retired senior schools inspector, that it was switching his portfolio from direct equities into two of its own unit trusts, the Extra Income and UK Income trusts.
The reason given was that dealing costs on the equities had become too high.
Shifting Mr Coxall's funds into these two unit trusts would not only cost him nothing in initial charges, it would also give him a far wider investment spread, making his portfolio more financially secure, he was told.
Mr Coxall is unconvinced. He says: 'Shortly before the funds were moved my investment was worth more than pounds 8,000, even after income was taken. It is now worth only pounds 6,700, a rise of just 5 per cent in four years.'
The two trusts in which his money has been placed have delivered steady, if unspectacular returns. The UK Income Fund is roughly midway up the range of the 103 funds in its sector, showing growth of 3.17 per cent in the past 12 months. Income has been 3.7 per cent over that period.
The Extra Income Trust is in 17th place out of 41 funds in its sector, showing growth of 3.93 per cent in the past year. Income has been 5.4 per cent over that period.
Mr Coxall says: 'I still do not understand why they decided to switch me from the shares into their unit trusts.
'To my untrained eye a large part of the losses suffered on my funds with Invesco have followed that decision.'
An Invesco spokeswoman said: 'The decision to invest in these unit trusts was taken in order to reduce dealing charges and achieve a wider spread of risks.
'The decision was widely trailed and clients were informed in writing in April this year. Unfortunately, the move took place at a time when the market was falling.
'That was the cause for the drop in value of the fund, not the switch itself.'
Write to Money Grouse, The Independent, 40 City Road, London EC1Y 2DB. Please do not send SAEs or original documents as we cannot guarantee to deal with every letter personally.Reuse content