Two more grants worth £2,500 have boosted the total given by the Round Tower Churches Society to more than £150,000.

Since it was formed 40 years ago by retired television engineer Bill Goode, the charity has donated surplus funds to help maintain the region's rich heritage of round tower churches.

Stuart Bowell, chairman, told about 35 members at the 40th annual meeting that it had made grants of £21,450 to more than a dozen churches in the previous year. 'This is the most we've ever given in grants in a single year,' he added.

He told members that it had been decided to meet at St Peter's, Gunton, near Lowestoft, because the society had been founded there on September 1, 1973, by Mr Goode, who had also worshipped at the church. Members held a period of quiet reflection in memory of Mr Goode, who was the society's founder and had died in January 2008.

Mr Bowell said that the society, which has more than 550 members, had a very successful year and total funds were £18,559 – down from more than £31,000 in the previous 12 months. As the charity had been started to safeguard about 180 round tower churches, which were mostly in Norfolk and Suffolk, it was appropriate to provide financial help to maintain the buildings. The charity's first grant of £20 was made to Cranwich, near Mundford, which almost four decades later received the largest single award of £5,000 to help with the cost of re-thatching.

The grant officer, Nick Wiggin, said that it had been a record year for grants. Some of the church repair projects had been fairly simple but others had taken months from start to finish including one which had just been completed at Threxton – almost four years since the work started.

An application for help for two churches was also agreed. St Margaret's Church at Hardwick, near Long Stratton, which needed work costing £111,304 to retile the roof and restore the wall paintings, was given a £2,000 grant. The society had last made a grant of £50 to the church in 1986, said Mr Wiggin.

It was decided to help with the urgent repair of stonework and the leadwork costing £7,000 on the round tower St Peter's Church, Rockland St Peter, near Attleborough. Since 2001, the society had given £2,650 towards the re-thatching of the chancel roof. Members approved a further £500 grant.

'This will mean that the society has now given a total of £150,500 over the past 40 years,' said Mr Bowell.

The total of grants last year to round tower churches of £21,450 included the following: £3,000 to Swainsthorpe and Herringfleet; £2,000 to Potter Heigham, Gayton Thorpe, Stockton, Brampton, Bawburgh and Croxton, and £1,000 to Yaxham, Taverham, Hemblington.

Earlier more than 50 members had a conducted tour of three chuches, St Margaret's Herringfleet, near Somerleyon, then St Mary the Virgin, Blundeston and St Peter's Gunton.