We are based in the US so the I cannot comment on the license requirements in the UK, but I can recommend that you do not use the pre-programmed frequencies in those radios until you find out what they are and confirm with OFCOM for the rules and regulations in your country.
As for the antennas, we would need to know more about the radios themselves and how you plan to use them. What make and model of Motorolas are they? Are they all the same or different? If you are using them outdoors, what is the specific application? What is the terrain? How far is “far away”?