Internal manhole cover - fitting and cost

Heyyouguys

Hello all

Really hoping you can help me. 

We have an old extension in the house we bought, which was built over a manhole (so this is situated in the middle of the kitchen). We have been having rat problems, and the drainage surveyors tried to access the manhole to survey the drains. However they cannot access the drain as the manhole is currently covered with a sheet of plywood, with grouted granite tiles on top of the plywood.

I want to replace this with a double/triple sealed and recessed (so we can put the existing tiles back on) internal manhole cover so we have easy access to the drains in the long term, and with no smells. However I have no idea where to start with this, especially who would do this kind of job and how much it would cost? Has anyone had this done in the past?

TIA and stay safe

DOH_a

Can the manhole be re-located to outside the extension resulting in the existing being removed completely?

Is it a private or public sewer/manhole?

Heyyouguys

No it cannot, at least for the moment. We are planning to do building work in a few years and at that point, I will look to relocate it. I believe it is the private section (at least according to my conveyancer checks)

DOH_a

A builder or handyman could carry this out for you. Either search via Google, obtain some recommendations or have a walk around the area to see if anybody is having works carried out.

Doozergirl

Are you getting smells now? 

I wouldn't move it for CCTV.  In most circumstances neighbours will have near access.   

It's your pest controllers that want to locate the likely entry points.  If you look hard enough will become pretty obvious and your weakest points are unlikely to be under all of that.  

An endoscopic camera, getting it behind kitchen units etc is an idea.  The rats will get through much smaller holes than you imagine.  Arm yourselves with expanding foam
and wire wool. 

Heyyouguys

Thank you @Doozergirl - we actually do not have them coming into the house (almost every entry point is blocked), but keep hearing/smelling them under the floors, in the walls, running up the soil pipe (which is boxed inside the kitchen), and then in the flat roof of the extension ceiling. I therefore want them completely gone and not able to access the house at all, and the drains are the most likely  source of their entry into the house fabric, so wanted the drain survey and rat blocker installed as a long term solution.

Can I ask what you mean by "neighbours will have near access" to my drain network? 

Heyyouguys

Update: We had someone come out to take a look. Turns out the tiles are grouted onto a large piece of plywood, which has in turn been screwed to the joists surrounding the manhole. 
My question - has anyone seen this before? How normal is it?

The person that came out said in the longterm to move the manhole into the garden (a good idea) but quoted us £3500 to move it 4m away. Does this quote look reasonable - it seemed high to me? Thanks in advance for your thoughts