That would depend on the length and overall cost of the project, say for argument sake, the project is going to be 1 year long and you have x amount of staff on site, Dependent on how much H&S the main contractor wants you could employ the services of a Health & safety professional to do a weekly Audit and even some onsite training as an when required. most companies will give you a set price for a Years contact to turn up one a week. Secondly invest in extra training for your own staff, SSSTS, SMSTS for Supervisors and Mangers, general operatives could do IOSH's passport to safety course, Train your site Supervisors and managers to give Toolbox talks, DABS (Daily Activity Briefs) and Do regular inspections, Which should be part of their role at the site. They can Ensure RAMs are current and kept up to date, with any revisions done and submitted if the work process changes or their as been an incident which means the Method statement will need to be updated. That shouldn't cost anything as it should be part of their job description.

Chris, You can do this pretty easy to be honest, Things like Hi vis you can work out at say one a month, Boots Hard hats Probably 6 months, Glove ideally based on what we do last about a week dependant on the Job, Safety Specs about a month. The you have Job specific PPE like welding masks, Gaunlets, Flame proof overalls, Safety Harnesses etc.. You really need to break it all down as PPE requirements can be cheaper for some trades than others. Best thing to do is list all the trades and then a list of all the relevant PPE that they would use and How Often it would need to be replaced, Be honest with this and you'll get a true figure, if you say a pair of safety specs will last all year then your kidding no one but yourself. Good luck and let us know what figure per person you came up with