I’ve applied to change my hours from full time to 3 days in a block ( ideally Tues-Thurs) on returning from maternity via flexible working application.  I’ve just had an initial discussion with my manager.  My boss has 3 team leader under him with 3 teams.  2 teams (A&B) do the same role (support 1st & 2nd tier) and the other team (C) logs cases and admin.  I’m a team leader of team A (5 staff).  Team leader B works 9-3 every day.  Team leader C works 9.5.30 Wed & fri and has only 1 team member. 

My Manager suggested I return to work Mon, Tues & Thur to go opposite team leader C as it was a good fit for the business.  I pointed out we had different teams/roles/tasks and only similar part of the job was team leader which is about 25-30% of the job. 

I asked what team I would be leading and he wouldn’t confirm if I would be sharing team C or going back to my old team A.  My manager has been happy with the person covering my job from within my team and he hinted that he would like to keep him happy and in team leader position.

Is the reason its best fit for the business a valid reason for not allowing me to do 3 days requested?

My nursery doesn’t have space on Mondays currently, I have 6mth old twins so hard to find nursery with spaces.