entering the \ IPv6 address with the colons does not work, neither the typical approach of enclosing the address in  brackets
So I just found this forum post which explains the problem and the solution.
Apparently the Windows Explorer can't handle colons, so the work-around to replace the : with - and then end the end the address with .ipv6-literal.net
well the first problem is that the semi colon is not supported with unc file name eg \sharename
Literal IPv6 addresses in network resource identifiers Since an IPv6 address contains colon (":") characters, network administrators must take care to avoid conflicts with other syntactic meanings of the colon in network resource labels. In IPv4 the colon is used to separate an IP address from a transport protocol port number. This usage has been extended to IPv6, however, when a port is specified in an address string, the proper IPv6 address must be enclosed in square brackets ("[", "]"). This convention is used in other more complex identifiers. Example: In a URL the IPv6-Address is enclosed in brackets, e.g., http://[2001:0db8:85a3:08d3:1319:8a2e:0370:7348]/. If the URL also contains a port number the notation is: https://[2001:0db8:85a3:08d3:1319:8a...7344]:443/This is not only useful but mandated when using shortform: https://[2001:db8::1428:57ab]:443/Additional information can be found in "RFC 2732 - Format for Literal IPv6 Addresses in URL's" and "RFC 3986 - Uniform Resource Identifier (URI): Generic Syntax." In Microsoft Windows operating systems, IP addresses were also allowed in Uniform Naming Convention (UNC) path names. Since the colon is an illegal character in a UNC path name, the use of IPv6 addresses is also illegal in UNC names. For this reason, Microsoft has registered a second-level Internet domain, ipv6-literal.net, as a means to facilitate symbolic substitution. IPv6 addresses may be transcribed in the following fashion: 2001:0db8:85a3:08d3:1319:8a2e:0370:7348 is written as2001-db8-85a3-8d3-1319-8a2e-370-7348.ipv6-literal.netThis notation is automatically resolved by Microsoft software without DNS queries to any nameservers. If the IPv6 address contains a zone index, it is appended to the address portion after an 's' character: fe80--1s4.ipv6-literal.net.source wikipediaIPv6 - Wikipedia, the free encyclopedia