I'm far from an expert, but let me share my experience with you:

At that level of turnover, you'd technically qualify for the "small business" tax rate - which is nice. I cant even remember the exact rate, but any tax blurb or the sars website will tell you it (high income free threshold and lowish tax rates)

but... your big problem is being deemed to be a "Personal Services Company" - in which case SARS will want to deem you as an employee and pay PAYE as though you were an employee. There are requirements to avoid being subjected to this treatment - a minimum number of employees who are not connected to the members (as it turns out I have a Cpl of employees who are administrative staff who might also happen to coincidentally perform domestic services from time to time), and the company cannot make more than a certain % of its revenue from only one client. Please google it or search at the SARS website for the exact current parameters. Your accountant will advise you of this also. I would not be identifying my business as a consultancy, but as a company that "exports services" or, even better "exports goods".

The downside to structuring things so as to avoid the Personal Services issue is a bunch of admin - you'll have to register for PAYE/UIF and pay UIF on those employees, you'll have to submit EMP201s every month to SARS and twice a year submit EMP501 declarations - a bit of a pain in the ass, but really not more than a few minutes a month (and a Cpl of hours twice a year).

I would recommend heartily not registering for VAT until you are obliged to do so when your revenue exceeds R1m per annum. Getting into the VAT return admin is just a right pain in the ass as far as I am concerned.

The alternative you should discuss with your accountant is working as a contractor (not thru the company) and asking for a directive from SARS to deduct tax at something like 20% - I know people who have done it this way who essentially have worked for one client, but have no specific insight into it myself. Your accountant can talk you through this.

Are you invoicing in rands or pounds? Be very mindful of the possibility that you invoice a rand amount and convert it to pounds, which your client pays, only for your local bank to absolutely screw you with the conversion forex rate! I have dealt with this on a regular basis and utilise a guy who negotiates on my behalf for something not far from spot for a 0.5% fee (less if you provide him with regular business, perhaps).

Do you need all the money in SA? If not, I would suggest you consider an offshore company + bank account in eg the Seychelles - and use that to invoice your client (assuming they are amenable). Getting money into SA through your own company in turn is a tricky business and not the sort of area one should discuss in public, but if you are keen to explore then can talk you through some of the issues I manage privately.

Hope this helps.
AMB