I've had a lot of dealings with various comapnies who supply monitoring equipment. Yes I do understand the regs, but there are new devices out there which do not meet ISO5349 hut claim to be accurate enough to not really need to. They potentially save a lot of time and also remove inaccuracies caused by a lack of understanding when it comes to accelorometer fitting. However they seem to clash with HSE advice. I have some very slick marketing info but I am not comfortable with these units. What do you think?

They are unlikely more than just a tool timer, you would still need to know the "rough" emmission value - which the manufacturers can give you or you can use from the table / list provided by the HSE.  This should give you a maximum useage time for each tool for either action or limit level which you can use as the basis for your risk assessment given your knowledge of how long the task takes and what you already know about the trigger times by talking to or observing the workforce.