Radio R6500 aerial connector

Hello,
I hope one of you can help me please.
I am trying to connect a radio to the aerial and the fitting on the back will not accept the aerial.
I have seen on some R6500 units an angled piece which goes in to this.I do not have this parkas I bought it secondhand..

Can anyone tell me what i need to buy please? or is it a lost cause.
I went to Halfords who ewer every unhelpful
thank you
Regards

Could have a look at these guys:
http://www.caraudiodirect.co.uk/

https://www.ebay.co.uk/itm/Car-radi...903379?hash=item20c4466d93:g:nv0AAOxyrjZRqkD5 may be what you want.

Thank you.
I tried one of these in halfords and the pin is to big, the hole is between 3- 3.3mm by using a drill to measure it.
I thought I could drill it out.
I will order one and see thank you gents.
I saw in some adverts for AR6500 an angled part which connected to it, thought it might be an OEM only.