Sorry for taking so long to come back to you CheeseStraw...
As you're not a Ltd company, all the income is considered your 'wages'. This is calculated after all your allowable outgoings.
As it's the main source of income for you both collectively, it makes no real difference how much you 'pay' yourselves (provided you live together), for the sake of benefits etc.
I think your best bet is to apply for tax credits (working and child). The amount you can claim depends upon what your collective income is and how many hours you work.
I think the thing to bear in mind is that all your marketing, menu development, research, sales time is considered 'work'. I say this because it is highly likely that, although you may not spend over thirty hours a week each on carrying out the main function of service delivery, it is highly likely that you both spend over thirty hours a week doing work that you anticipate will lead to income. As such, any claim you make should reflect ALL the hours you put into building your business.
As far as all the other employment benefits are concerned (maternity/paternity, statutory sick pay etc), that's down to the company...i.e. you! It is reclaimable through HMRC but I would take one step at a time and make the tax credits claim a priority.
If you need a hand, message me and I'll be happy to help.