hiya folks found this in march BSH page 3 clarifying the effects of the licence/category change for trikes

TRIKES:
As of January 19th 2013, all trikes become part of the motorcycle 'Category A' licence. To ride a trike, you first have to pass a test on a solo motorcycle. Strictly speaking, you could ride a trike after passing the A1 and A2 tests, but that trike would have to comply with the same power limit restrictions and power-to- weight ratios set down for solo motorcycles. After passing the Category A test on a solo motorcycle, either via staged access or direct access, you can then ride any size or type of trike you like.
People who hold a licence with a provisional B1 category will still be entitled to ride trikes up to a gross weight of 550kg on L-plates without taking a CBT (NB The B1 category was an automatic entitlement with a motorcycle licence prior to 1999, but licences issued during and after 1999 have no B1 entitlement). All trikes, car or bike engined and whatever their weight, now fall in the Category A licence.
To put it plainly, you cannot now ride a trike on a provisional licence and you cannot take a test on a trike, unless you are disabled (see below) or you have a B1 provisional category shown on your licence (NB. If you've held a full category B car licence prior to January 19th 2013, you can still ride any trike you like. These changes only affect people who did not hold a full car or bike licence prior to that date).
The DVLA has also confirmed that those who hold a current provisional licence issued prior to 2013 stating B or B1 do, in fact, have 'grandfather rights' for the duration of that licence (old paper licences last until the age of 70 but photo licences only last 10 years upon renewal of the latter, this grandfather entitlement will be lost)

DISABLED PEOPLE AND TRIKES:
Those with disabilities who cannot ride adapted solo motorcycles will still be able to ride an unrestricted trike on a provisional licence and take a test on an unrestricted trike. However, as this will now need a provisional motorcycle licence, a CBT course must be completed before going on the road, and that CBT will last just two years.
On passing a test on a trike (having taken the theory test), a disabled person would have a category A licence restricted to trikes only

                                                                                                                                                                             

  'Clarity', are ya sure? lol      I wish I had a good memory                                                                                                                                                                             

I've always thought it was insane to allow people with only a car license to ride trikes.                                                                                                                                                                                

i think its also why ya see sooo many trikes at rallies now.... coz you can ride em on a car licence!!   the bit i dont understand is how is a rider with disabilty going to do the cbt?                                                                                                                                                                             

You've always been able to use a combo to do the CBT if you are registered disabled and can't handle a solo so I assume it will be the same course for a trike.
                                                                                                                                                                             

Can you please PM me , I trying to find where its states in law this bit about disability PL unrestricted and cbt and L plates part still ,                                                                                                                                                                             

People with disabilities are the only ones who can take a test on a trike.From Jan 19th 2013 you have to take a test for a trike. Before jan 19th 2013 if you already have a full car licence you can ride a trike.                                                                                                                                                                             

Hi, regarding trikes, I have held a full motorcycle and and licence since the eighties, I still have a paper licence. The part which concerned me was that grandfather rights only lasted the life of the licence. What does this mean to me at age 70? I have no desire to own a trike at the moment though I have ridden them on occacions, but by that time I might feel the need. Will I be able to?