Drell-Yan-type processes in QED are considered. The dependence on the factorisation scale choice in radiative corrections due to radiation from the initial state in electron-positron annihilation processes is investigated. The results of applying different factorisation scale prescriptions in the leading and next-to-leading logarithmic approximations are compared. Analytical expressions for corrections to the cross sections of these processes, obtained by direct calculations and those obtained using the QED parton distribution method, are used for the analysis.