Is it safe for me to have 2 Flu vaccinations in 1 season?

It is not normally necessary or recommended to have multiple flu vaccinations in the same flu season, but if you do, it does not cause harm.

Current flu vaccines protect against 4-strains (quadrivalent flu jabs). Vaccines for people 65 years and older may be “adjuvanted” to produce a greater immune response, or may contain a higher dose of antigen. In theory, the same effect could be achieved by giving two doses of standard vaccine, though there is not normally any reason to do this. 

A second or subsequent dose of flu vaccine, whether intentional or inadvertent, would not be expected to cause harm.