So you have never passed your bike test? In that case I think you will need to pass your test on a 125cc first and then go up another class before going limitless, its been a long time since I rode motorbikes :-(
I wish you well and so glad you are going for a Harley, so much nicer and more sophisticated than these lie flat scream machines!!
I don't envy your insurance premiums on a big bike.
I love these! Media URL: https://www.google.co.uk/search?q=harley+trike&espv=210&es_sm=93&source=lnms&tbm=isch&sa=X&ei=icQoU4eFBuep4ATh-4GAAw&ved=0CAkQ_AUoAQ Description:
Firstly you need to add a Provisional Bike entitlement to your car licence (free).
You’ll then need to complete compulsory basic training (CBT) and take the theory and practical tests for the kind of motorbike you want to ride within 2 years.
If you are over 24 you can take your test on a category A bike (large motorcycle) - but you can only practise on the public road under the supervision of an instructor.
I wish you hadn't said that SD, I've just checked my Photocard Licence and there's no mention of Bikes on there, changed it last year when we moved, was on a Photocard for a year or two before then, don't remember if it was on that one or not tbh. I've still got the 'Cardboard' one from when I passed my MC test, I'm just wondering if the grief of trying to sort it would be worth it.
No you DO have to take a theory test again, i *think* its a different test, ie has motorbike questions in as well, also you need to do the hazard perception test as well.