Two consortiums of business and professional people have paid £35 million for the two final office investments in the Custom House Plaza scheme at Dublin's International Financial Services Centre. The investments will produce a return of almost 5 per cent for the 12 investors in the two groups, in addition to 100 per cent capital allowances. It is understood the groups include several leading barristers, as well as accountants and businessmen.

Under changes announced in last December's Budget, capital allowances in the Dublin docklands were reduced to £25,000 per annum because of the number of top earners paying little or no income tax. Office developments currently under way in the IFSC have not been affected by the changes.

The sales means that Mr Brian Rhatigan's company has now sold all phases of the Custom House Plaza scheme. The 175,000 sq ft development on the site of the former Sheriff Street Sorting Office has been completed within three years. The investments have been sold for more than £85 million. The Hardwicke/British Land consortium, which had exclusive development rights for the remainder of the IFSC, is near to completing its final buildings on the site. Ann Hargaden of Lisney, who handled sales in the Custom House Plaza, said yesterday she was not in a position to comment on Plaza 5 and 6, the final two office blocks in the scheme.

Both blocks have been rented at £27.50 per sq ft, with a further £1,250 for car-parking spaces.

Plaza 5, which was sold for £20 million, has 35,000 sq ft of office space. It has been let to a major computer software company under a 25-year lease with no break options.

The company will not qualify for the usual 10 per cent corporation tax because it is not licensed to trade there. However, it will be able to claim double rent allowances and a remission of rates.

Plaza 6, a 24,000 sq ft block sold for £15 million, has been let to a European fund management company. It is also to occupy the ground floor of Plaza 5.

With over one million sq ft of offices completed in the IFSC, attention has now switched to the 12-acre extension where several more blocks are to be developed for Citibank, Bank of Ireland and Goodbody stockbrokers. The remainder of the site will accommodate about 400 apartments.