The driving without a licence will carry 3- 6 points and a fine of between 125-175% of your weekly income.
However, the speeding will attract either 6 points or a short ban of between 7 - 56 days. Also, the fine will be 125-175% of your weekly income.
I would imagine they would just fine you for one offence and add points or ban. A ban is more likely in the circumstances.
There will be costs of £85 and the victim surcharge of roughly 10% of the fine.
There is also the issue that they will charge for no insurance even if they haven't done it now. That will carry 6 points or a ban and a further fine although probably the entire conduct would lead to a ban and one single fine.
In terms of minimising the sentence, I'm afraid it is really too late now if you have sent the letter. You have aggravated the sentence several times over. If you have said that your husband wouldn't allow you to drive the Bench will perceive that as an excuse as ultimately only you were responsible for your driving licence. If you have said that you were driving a child around unlicensed and uninsured then that is not going to go down well.
Sorry but I can only give you truthful information.
Can I clarify anything for you?