I had the same the first time. But look very closely. There is a C-clip that sits on the axel-pin in the middle (seen from the top). Remove that, but be careful that it doesn’t jump away. When removed, you can lift the inner disc with the strobe markings.  

Thanks for the advice - I got the strobe and rubber mat off - hoping to see some screws I could undo to remove the platter - sadly they appear to be rivets. Any further suggestions welcomed. Login to view image

If I remember well, you should be able to lift the platter up/out.

Nope - still firmly fixed. I'll go in from underneath and see what I find.

I'm properly baffled by this TT! I have accessed the underside and there is nothing there which might release the platter. In the photo of the spindle housing you should be able to make out a black cog - which doesn't appear to engage with anything! And the last pic shows a cutout in the plate through which you can see the underside of the platter. As I turn the platter by hand occasionally bits of mangled belt appear - but how could you replace a belt with no access to the motor under the platter? There's no cutouts in the platter for locating a belt on the drive spindle - er - as I say - baffled !!

Are you able to rotate the platter, or is it stuck? For your information, the platter you are trying to remove, looks like this from the bottom side:   Login to view image

Platter rotates quite freely but gets tight occasionally - I guess when the mangled belt makes it stick.

I took my BeoGram 1000 out of storage to check how my platter gets disassembled. With my BeoGram 1000 it's a 2 step:

1. Remove the C-clip to remove the inner (plastic) plate with the strobe markings.
2. Remove 3 screws on the main plate, to lift it from it's holder (see the 2 pictures).

In your case, the 3 screws are rivets. So lifting the platter won't work the way it does for me. Though:

• If you need to check the suspension, the platter doesn't have to be removed. For suspension you need to get the acces via the bottom of the plinth.
• If you need to replace the driving belt, there are ways (not the easiest ones) to do that with the platter in its normal position (for instance Login to view image   Login to view image