The "new" offices in Old Hall Street or St Pauls Square replaced older 60's & 70's built offices and the site of the Stadium which was demolished in the 1970/80's and had been a car park for many years. The Passport Office was built on the site of the old St John's Eye Hospital, I think in the late 1990's. The Echo building has been around since the 1970's, whilst the Plaza dates from the 1960's as was the former home of the Littlewoods empire. The last time I looked much of the new offices in St Pauls square were unoccupied, but there are many other buildings which were empty or near empty, for example Exchange Flags, Albion House (recently reopened as a hotel), Sun Alliance Building (now a hotel), India Buildings, Martins Bank Building, and of course the HMRC office at Queens Dock which has recently been sold and the Municipal Annex in Dale Street that is now a hotel and many more small offices across the city centre. The Cotton Exchange and Corn Exchange also had low occupancies but have been slowly refurbished with positive results. The result is that office rents in Liverpool are much lower than for example Manchester which whilst it might be good for tenants, but it also means investors are reluctant to spend huge amounts of money refurbishing large buildings with little prospect of recovering their investment which is why I believe Liverpool City Council placed a block on the building of new office accommodation in the city centre. Yes many of these empty or near empty buildings housed banking and insurance companies which moved out, mainly due to mergers, and advances in technology which made centralisation easier and call centres in India etc. In contrast whilst shipping has gone down a similar route, the city still has probably the largest number of shipping lines offices in the country, even though many bank room functions are now completed in India, China and the Phillipines. Those shipping lines include many of the top 10 global shipping lines, including Maersk Line (UK headoffice), MSC, CMA-CGM (UK Head Office), Hapag Lloyd, CSAV (UK head office - just acquired by Hapag Lloyd so further amalgamation likely next year), ACL (European head office - it also handles all the documentation for it's offices in Europe and North America and UK Grimaldi services), NYK (UK Head office), Zim Line (UK Head office). These liner shipping companies also support a large freight forwarding community, whilst the port in general supports a wide range ancillary jobs, although not all of these are in city centre.
Sadly, despite the success in the shipping industry the city has probably a net loss in the number of people employed in the industry but which should be reversed when Liverpool2 comes on stream towards the end of next year. However, many of these jobs are unlikely to be in the city centre as they are likely to be the distribution field and thus probably on the outskirts of the city.