Hi Sarah
I am guessing from the content of your posting that generally your organisation works as a sub-contractor on site, STILL with CDM duties but not quite as many as the Principal Conractor has.
My view is strongly in favour of SMSTS before some CDM course, for various reasons.
I've been dealing with CDM from the days when the acronym for the draft of the first iteration of CDM was still CONDAM.
CONDAM was all about "transposing" only the management requirements of the EC Temporary or Mobile Sites Directive with what is now in Part 4 of CDM 2015 dealt with by consolidation of many of the requirements of four codes of Construction Regulations 1961 and 1966 into the Construction (Health, Safety and Welfare) Regulations 1996 with not much amendment, other than to try and deal with some of the myths, such as the perception that if a trench was less than 1.2m deep it couldn't be dangerous [The Regulations did NOT say this, but could be easily misread to be interpreted as such - and probably often deliberately done to cut corners - I know as I worked in an HSE Construction Group in the late 1980s, so I heard all the excuses!!]
So, those 1996 Regulations didn't mean a lot of training for Contractors as in effect they told them to do what they SHOULD have been doing since the 1960s.
So CDM 1994 focused on the management duties on the Client (and Client's Agents), Designer, Planning Supervisor (now Principal Designer), Principal Contractor and Contractor, with often more than one of each of these duty holders.
Absolutely nowt to do with saying that e.g. measures need to be taken to prevent excavations collapsing and injuring people. That was in the 1996 Regs when they had been made and in the 1960s Regs until it happened.
This meant that training programmes focused on those management issues and most programmes managed to avoid getting side tracked into the nuts and bolts of what happens on the ground of a construction site (other than training, supervision etc).
I developed and delivered many CDM courses ranging from a day's duration to 3 days aimed at the new role of Planning Supervisor (as we were going to be doing a lot of that!).
Duie to some politics and trying to present some non-existent "deregulation" what happened next was that in 2007 the requirements of CDM 1994 and CHSWR 1996 were consolidated into a single code of regulations - one less code but one much longer code!
....and many of those offering training courses now tried to cover the whole shebang.
Since, lots of people find it difficult to justify putting LOTS of people on course lasting more than a day, the trainers tried to put together one day programmes that covered everything in CDM 2007 in say 6 hours.
Inevitably this meant that at least a third of that programme would be devoted to Part 4 - the nuts and bolts stuff.
Result - not enough time was given to what the thrust of CDM 1994 was about. The greatest opportunity to reduce risks on a construction site is at the outset of the project - when decisions are made by Clients and Designers which can make life inherently easier for the Contractors - or not.
But in your stage of your career, you are probably mostly dealing with done deals - with the exception of e.g. Temporary Works and changes to Design - so those you are trying to look after are faced with making the best of what it says in the specification and drawings.
At this point it is precisely Part 4 of CDM + other things that used to be in the Construction Regulations 1961 but which got moved elsewhere, e.g. work at heights, lifting operations that you need to know about. Can't cover all this in 2 hours!!!!
- which is why SMSTS takes a week.
It is the gold standard that is tried and tested and, apart from anything else it will show you what is covered in the training that your site managers are likely to have attended and hopefully learned from.
This is not to downplay the importance of CDM including the management bits that apply to PCs and Contractors, but the chances are that your managers and supervisors are up to speed with those and you can learn by a bit of reading (L153, though you might want to look at L144 which was much better - IMHO - which supported CDM 2007) and on the job.
Once you are comfortable with the nuts and bolts stuff, perhaps THEN time to seek out a CDM course that has a programme that entirely or at least largely ignores Part 4 and sticks to the management aspects.
Then you would be better placed to help your employer feed back on the poor decisions that have been made at the front end of the project, and which may well be why your employer is making a "claim".