Live and learn. Accountant hasn`t mentioned anything ever regarding VAT.
So it is actually beneficial being VAT registered for IT consultant, because he would earn extra 5.5% from VAT.
Its slightly different to this.
Lets say you are currently not VAT registered and you charge £100. You receive £100 and that's the end of it
If you are flat rate VAT registered on 14.5% then you charge £100. Your bill is actually £120 (you customer reclaims £20 so it only costs them £100).
You however receive £120 cash. Its this amount you apply 14.5% to - the gross amount. So of the additional £20 you've received, you pay over £17.40p to HMRC making £2.60p.
You're still up but not by as much as you initially thought.
However(!) you are not allowed to reclaim any of the VAT you have suffered on expenses.
If your associated VATable costs (including VAT) were more than £13 (£2.6/20% from a purely VAT calc perspective, you would be worse off, not better off.
The moral of the story - HMRC don't give money away in general. You need to run the specific numbers for your own business to see whether its worth it.
Administratively it may be a benefit as its easier (especially on the annual scheme) and of course there is the first year discount of 1% which can be beneficial, but as always - it depends!