1960's chimney already lined?

[audiobull]

I have not been living here long so do not know much about it. It is a 1960's property and when we moved in the fireplace was a nice cupboard.

I measured up today and drilled a test hole to come out in the chimney (luckily) and then had a bit more of a open up to find myself coming up inside of a stainless flue?
The flue then seems to reduce into something else and is cemented into this smaller one. I can see light at the top but it is need of a clean before I can be more certain. It would seem the flue was cut and plasterboard put over the hole and the rest made into a cupboard.

I have a Jetmaster universal 600 to be installed. Can I get a gather and then with some flue go straight into this stainless flue and then build up the front to the Jetmaster after cleaning? It all sounds too simple to me unless I am lucky on this occasion. pics below of space and flue.

 

[audiobull]

I have now ripped the cupboard out and cleaned up the fire a little and put it in place.

I have just measured and flue is 5". Seems to be concrete in.

 

[audiobull]

Has no one seen this before? I cannot use the Jetmaster as they require a minimum of 7" flue so I guess I will have to go for a defra approved 5" required log burner?

 

[Wisneaky]

It's hard for me to tell. I think you'd have to get a chimney sweep out to inspect it. I'd be against using it until it's professionally inspected and made sure that it's up to code.

 

[mass_burner]

Chimney liner is not a thing to go vintage on, get it checked out/replacement.