Sole Trader vs Limited Company

[NewJobNewMeNewLife]

At the moment I contract as a sole trader. I am earning approx £18k as a sole trader (contracting) and I earn £42000 PAYE for in a different role (0.8 FTE)
I have the opportunity now to increase my contracting work but it would mean leaving my employment- I would be earning approx £65k as a sole trader.

At the moment, I do my accounts for my tax return myself. I am trying to calculate whether I would be better off with this opportunity or not- and if so, by approximately how much.
My model is giving advice- so there are few costs and I would need to register for VAT.
I have calculated as a sole trader, I would gain marginally (£5k minus deductions) but lose some job security/ benefits (sick pay, redundancy etc.) however if I was to swap to a limited company would the benefit be bigger to me.

I would prefer to do the contracting full time, but I am trying to see what the costs/ benefits would be before I make a final decision. Any help would be much appreciated!

We moved from sole trader to limited company about 18 years before our shop closed due to high street retail downturn. Best thing we did. It cost us more in accountancy fees over the years, but with hindsight it was well worth the extra cost. We had high overheads, rent, suppliers etc. We got everyone paid before we went, but we had protection from the landlord who could have come after us for rent for the remainder of the lease, if we were not limited. In your case, you don't have the overheads, but say you were taken ill, couldn't work, spent your savings then got a big tax bill to pay? As a ltd Co, the company would owe the tax, not the person.