1) Where do I get the binaries to install on windows - is it just the normal vCenter for Windows install package?
The binaries are incuded in the windows version of vCenter install package
2) Does it require a database and if so, will it install a local DB (my install is only a couple of ESXi hosts)
Yes a DB is required it can be either a local or remote but Update manager require a 32 bit DSN ODBC Connectivity