Worth doing? Although I have used a tacho in the past it was about 6 years ago . I see there is one school doing a tacho course for £35…only four hours but covers both analogue and digital tachos.
They also do drivers hours and WTD for £100 .Im sure its not going to be too in depth and cover all the intricacies (sp) but at least it will give me an understanding of the regs…wont it?
Or better just saving me money?
That sounds like a good idea to me and money well spent. My first tacho job wa running under domestic rules and I confess to still not fully understanding as much as I should. 
My other half (repton) gets frequent phone calls from me querying what I should do in any given situation. So if you have found an affordable way to eliminate the confusion then go for it. 
I would think that the Tacho one for £35 is just on operating the tacho unit as they do a different course covering the hours regulations and WTD. Might be worth doing that one first as it may well cover what is in the £35 course anyway.
instead of doing the tacho course ,would I be just as well of buying this :
The Pocket Guide to LGV Drivers’ Hours and Tachography Law: Including Working Time and Minimum Pay Rules (Paperback)
It is written by the main man when it comes to this sort of thing, David Lowe, so it will cover everything you need to know.