One benefit many overlook is the ability to register for VAT. People often worry this makes them more expensive but if you’re contracting to other VAT registered companies you’re not – as they can claim it back.
The advantage in your situation of going VAT registered is that you can go on a Flat Rate VAT scheme. You basically charge 20% VAT and only pass on somewhere between 11% and 14% to the VAT man – netting you 6% to 9% margin.
As a single man LTD company it’s unlikely you’ll be buying anything significant with VAT on so this works massively in your favour.