Further down the page you can see a list of PDF documents for each region, for example I clicked on Wales to get get the PDF document in my above comment and that lists every transmitter covered by that region along with the UHF channels they are using before the frequency change and the ones after.
So for example looking at the list you can see the next date of changes is the 17th July and the first transmitter listed is Carmel which is says is in Wales.
So looking at the PDF for wales again and scrolling to page 15, we can see that ON the 17th July 2019 -
PSB1 which currently on UHF 60, will change to UHF 23
PSB2 which is currently on UHF 53, will change to UHF 26
PSB3 which is currently on UHF 57 will change to UHF 29
COM4 which is currently on UHF 54 will change to UHF 33
COM5 which is currently on UHF 58 will change to UHF 36
COM6 which is currently on UHF 49 will change to UHF 48
Every single transmitter change for the rest of the year caused by the need to free up the 700MHz band, is listed in the PDF documents contained on that page.
Your team will need to create a database or something so that as each date passes the correct config for the chosen transmitter is updated.
EDIT: If what you mean is you don’t understand how the UHF channel maps to the actual MHz frequency in use - then here is a UK table: https://www.digitalspy.com/tech/terrestrial/a12613/uhf-channel-and-frequency-guide/
The UHF Channels 21-68 map the centre frequency listed in the table.
eg UHF 21 = 474MHz
