Self-employed consultant and maternity rights: ask the expert

My situation is rather complex. I am a self-employed sole trader providing consultancy services for a large financial firm in London but from a regional office. I work with two other partners and essentially I get paid a £10,000 per annum fixed retainer and other income which is split with the Head Office. It pretty much resembles a franchise model whereby our income and costs are split with the Head Office and whatever is left in the pot is then split between the partners. Anyhow, I am due to have my baby in June and I am planning to stop work for a month as soon as I give birth. Now my earnings are based on what I have generated over a year and I draw my income as and when I wish and pay tax on all earnings remitted to me in any tax year. Even though I will stop work for a month, I will still be paid my monthly retainer plus my agreed share of the income generated in the month although I can postpone the payment of both until next month or a later time. Indeed what I draw every month is irrelevant as I declare the yearly income on my tax return on a remittance basis. As I won’t be working in the period, will I be entitled to maternity allowance for the time I am away from the office? Sadly, I am pressured by my fellow partners to return to work as soon as possible if I wish to retain my share of earnings. Also, the time off I intend to take will need to be taken as holiday rather than sick or unpaid leave. My plan is to return to work for six weeks and then have two weeks off and again repeat this process two more times. Am I entitled to anything in the two week periods of absence from work? If so, how many stay in touch days am I  allowed to have in the two week periods, or in general in the first six months under the proposed plan? For your information, we have no formal partnership agreement regulating matters of maternity leave and pay, sick pay and pension provisions. However, I am aware that other regional offices of the same firm do have agreements in place allowing for six months’ maternity leave on full pay (i.e. retainer plus 100% of the agreed share of income) plus very generous pension provisions and sick leave. My fellow partners have refused to sign an agreement with these terms in the past. One more question. Since I work for one company and from the same office and also the same hours as individuals employed by the company, should I not be treated on an equal footing as an employee? My service contract makes no mention of maternity pay or rights and uses the word ‘worker’. However, I do believe that my fellow partners and I fulfil all of the criteria of a ’master and servant’. If so, how could the employee’s rights be exerted in my case? Would I need to seek legal advice and/or take the company to court? Obviously this is the last thing on my mind.