Hi Nadina,
Glad to hear there were no substantial challenges with your supervision process! This timing for edits may be average for the UK - I'm not actually sure! I do know in many universities in Canada it often takes 1-2 months to receive edits back for several dissertation chapters! I don't know if there's a way to adjust the timing of the edits, but do you think it would be helpful with planning out your dissertation and work/life schedule to be advised before you start your dissertation roughly how long marking drafts could take?