Need help with extension of spouse visa

[seekhelp]

need your help to understand maternity leave in the period of finacial requiremnt .
my spouse visa is expiring on 20/07/2016 , we are blessed with a baby in february 2016,I took on maternity leave from december 2015.
my husband works on hourly basis, we both worked with the same employer for more than 6 months(CatA) , he worked less hours since baby is born,I am on SMP that limits my earning too.
That is going to affect our total 6 months average earning in showing more than 18600.
If we were to take whole year earnings for both of us that goes well beyond 19000/year but since more than 6 months with one employer puts us in a situation where we got to show 6 months average earnings only,those 6 months have been affected by my maternity paid leave and husbands paternity leave (since baby is born ,husband got 2 weeks of paternity pay) after that he worked only 20 hours a week until April end. but from May he is full time at work earning 1600/month.
since this period is going to count in my application.I am worried that my visa might get rejected.

1) how can I use maternity affecting financial requirement information in my application to help present my case?

we are planning to apply for one day service ,
2) Can I apply on 15th of July? (visa expires on 20th July)

My husband is back in work full time since 1st of may ,his May and june salaries will give us, safer window .He is also offered a second job, where he is requirement to work only 25 hours /week.He hasn't accepted that yet.
3)as not sure whether it will affect the category we apply under?


Please kindly advice how do I present my application ?
Thank you all in advance !