Dissolved company still trading

I am enquiring as to whether it is legal that a company should continue to trade even though they have officially been dissolved.

I employed a loft conversion company to re-roof my loft flat roof and they carried out the work in March 2016. I paid cash for the work.

I have recently discovered that this company was officially dissolved before the work began.

The re-roofing that they carried out for me 30 months ago is now coming away from the loft and material from the roof has been found on my garden.

I contacted the builder and he came out to see me, checked the roof and admitted that they hadn’t carried out the work as well as they could and so when they come back they will make sure that the roof stays put. He also suggested that I go through the insurance company and then he will carry out the work once it has all been approved.

I did go through my insurance company but I haven’t re-employed this builder because I do not think it is right that he should be paid twice for the same job.

My question is, considering he was dissolved at the time he carried out the work on my roof and now I have found that he is still trading under the same name, is this legal and if not, is there any way that I can recover the money I paid him in March 2016 or at least part of it!