If it’s useful, I’m currently getting my class D through a job-centre referral to the ‘Employability Fund’ - might be a Scotland only thing, unsure of that… but I was offered the option of Cat C or Cat D… had already booked my C, so snatched (and I mean SNATCHED ! 
) the ‘D’ from them. Supposedly it comes with a guaranteed job/work placement afterwards… but, these courses do seem to be like gold-dust.
The eligibility requirements are a bit less stringent, there are over and under 25 versions, and you can get on it after >3 months of unemployment. Alternatively, if you’ve been made/taken redundancy, you can get on it immediately.
With that said, my JCP advisor told me that I am the first person shes ever seen actually get onto the course, despite having referred many others previously.