If you look at the early deeds of properties which formed part of the former Wivenhoe House Estate, following its acquisition by Thomas Harvey, the shipbuilder, and its disposal by auction in 1857 and 1861, you will repeatedly find the same reference to the Colchester Bankers who financed its development:
‘Whereas by Indenture dated the twenty third day of May One thousand eight hundred and sixty one and made between the said Thomas Harvey of the one part and the said John Bawtree George Henry Errington John Bawtree the younger and Jeremiah Haddock of the other part The piece of Land hereinafter described with other hereditaments was conveyed to them and their heirs by way of Mortgage for securing the sum of Three thousand One hundred and thirty one pounds thirteen shillings and four pence and Interest’
The firm was a well established business, formed as many banks were in the eighteenth century, by a local merchant who also offered banking services. In Colchester these services were offered by John Mills, a London tea dealer, who opened a tea warehouse and coffee shop in the High Street. By 1774 he was also involved in banking and in 1787 he opened the Colchester and Essex bank in partnership with his cousins John and Richard Twining of London, who were also tea merchants.
Later the Twinings retired from banking (although they continued to trade as a tea business in the Strand) and the partnership was dissolved in 1797. John Bawtree of Colchester joined the Bank which then became known as Mills, Bawtree and Co. John Mills died at the age of 87 in 1822 and he was succeeded by his son, John Fletcher Mills. Later his son in law, George Henry Errington became a partner and the firm was then known as Mills, Bawtree, Errington and Co.
In 1891 the bank failed and Gurneys Round Green and Co, in conjunction with Gurneys, Alexanders and Co of Ipswich and Sparrow Tufnell and Co, offered to provide funds for the immediate requirements of customers. The branches of Mills and Co ultimately went to these three banks and five years later were subsumed into what was to become Barclays Bank. See link below:
http://www.british-history.ac.uk/vch/essex/vol9/pp135-147 (under Banking and Insurance)