Whats the thingy called

[MHTTrading]

The ones in the pic are spiders, the solid ones that fit over the turntable spindle are spindle hubs or spindle adaptors (depending if you're posh or not)

[deltadelta48]

I think they are just called Inserts or (probably incorrectly) Spindle Size Adaptors.

I think you have got it. In US I think we called them spindle somethings!

[booksntings]

Definately called spiders, I have some if anyone needs them

[astral276]

I think you have got it. In US I think we called them spindle somethings!

I think the difference is that spiders (or inserts) are fitted to the individual records while a spindle size adaptor goes over the turntable spindle and the records are used without spiders.

Adaptor:

Attachment 14327

Spider:

Attachment 14328

[DoubleHappinessRecords]

Insert / spider

[SpecVinyl]

that goes in the middle of the vinyl as a replacement if the inner is missing. My mind has gone blank and I cannot think what the name of them are

It's called a '45rpm adapter'. It is also known by over names, but I'm pretty sure that is it's proper name.