So Ive used this website plenty over the years, but I only just accidentally found out it can generate point to point height elevation charts. Something id had to muck round with endless 3rd party websites trying to do the same thing with varying success. It will plot the line from the registered site location to your marker, so depending on your needs you may just have to 'reverse' the bearing.
Australian Communications and Media Authority (ACMA) Site Location Map. This page is part of the Register of Radiocommunication Licences (RRL). Find ACMA Sites by a map, lat/long or street address.