Sorry for the slow reply, which you will correctly interpret as 'I thought I'd posted this but have just discovered I hadn't actually done so.....D'oh.....'
I emailed Cabmasters about the A518/64RH, their chap Brian says £2k + VAT, only 2 left, buyer collects from just north of Manchester. Their photos suggest it comes with a torque converter. Their replies were quick and friendly. They are buyers of surplus OEM stock so may not know the full ins & outs of all their items so I think that if you want one then do plenty of research to make sure it'll work with your engine, adaptor plate notwithstanding. They are advertising them as suitable for some diesel trucks plus Aston Martins. So are they a diesel trans or a petrol car trans? According to Herman at
www.bigblockmopar.nl a diesel transmission has heavier duty internals which Herman thinks will be bad for economy in a petrol car.
Having said all that the photos show a part number of P52119161AB which when I searched on it comes up with Dodge Dakota/Ram 2wd truck transmission at
www.2040-Parts.com in NY, USA. Allegedly brand new OEM, $777! It's so unfair.....