I sympathise, and you might have a bit of a battle on your hands.
My situation took 6 months to get sorted and I had to go after everyone to get a resolution.
Firstly, the postcode checker is only going to tell you whether FTTC is available to property in your postcode area. It is correctly reporting that it is, as you have the cabinet near you to confirm.
The address and line checker is the accurate reflection of what is happening at your house. There are only a few ways that you are not showing the FTTC facility for your line and address.
1. You are not actually connected to the box. (Unlikely as you have confirmed via the tracker that your phone line is connected)
2. It is a records issue. Read on.
Your issue is most likely to be a records problem with BT Wholesale. When we had a new FTTC enabled cabinet installed a stones throw from my house last which went live last December, I was ecstatic. I had a fibre service from a further away box at 15mb, but now I would get massive speeds.
Suddenly one day, my 15mb speed dropped to 1.5mb and my 6 month of woes began.
I was able to check and see my phoneline had been moved to the new nearer FTTC cabinet, but yet when I checked my phenolic and address on the DSL checker I was getting a result like yours, i.e. 1.5mb service and no FTTC! (Checking my postcode however reflected FTTC at 80/20 was available!)
My neighbours (right up to 100m further down the road) run the checks, and they were connected to the same cab and getting a full 80/20 FTTC service even though they were further away.
Ultimately, it turned out to be a records update that BT needed to do. Easier said than done since most mainstream end providers (in my case Talktalk) haven't a clue how to deal with any problem that can't be resolved by unplugging your router for 5 mins! You cannot talk to BT directly nor will Openreach assist you.
My resolution? I was advised to go to Andrews and Arnold who are very good at rectifying these sort of issues. Indeed, so good that it took them just 2 days to sort out the problem I had been pulling my hair out with Talktalk about for 6 months!
I would urge you to read my story here, but its a long read

You may find it worthwhile
http://forums.thinkbroadband.com/fibre/4384066-issue...
I now have 75mb steady download and 19mb upload with A&A with excellent ping performance and no throttling. They are a bit more expensive than the mainstream providers but well worth it, and their customer service is second to none. These guys know there stuff. They have a short 6 month contract requirement, so you could even go to them and then change if needed, but I don't intend to after the agony I went through to resolve my issue.
Good luck!
Edited by deleted (Fri 21-Aug-15 12:14:26)