I don’t think anyone will be running training courses during the lockdown so you will probably need to wait until things are clearer before trying to book. When I did one I looked up Lantra training centres as they seem to do them most regularly.
Unfortunately my DSC1 was so long ago a separate WGMH ticket is required to register for DSC2, and my BDS Advanced Stalkers Certificate is apparently worthless these days. If I was a cynic I'd say someone has made a living out of this...
I'm surprised that nobody has not put an online distance learning version of the course together. I used to teach Advanced Food Hygiene online, this was designed to provide an opportunity ofr candidates to gain the Certificate without having to attend a "traditional" course, perhaps miles from home.
The other advantage was acess to an online tutor to discuss aspects of the programme. and to monitor learner's progress The challenge is to get exmaining bodies to agree the format and to have procedures in place to verify and audit candidates work and quality of instuction.