For lag indicators - you can use the HSE stats for the construction industry - all available via the HSE website.

You could benchmark against similar (or bigger) companies, rather against HSE construction accident statistics which include the reported (rather than reportable) performance of micros and SMEs which is substantially worse than average. You will find some stats for members of UK Contractors Group via google. Check whether UKCG or other contractors are maintaining stats only for their direct employees or also for their supply chains. Rates are likely to be higher if sub-contractors are included as the direct employees are usually mostly doing lower risk activities with substantial time in the site offices.

But OSHA is the US regulator. There are huge differences between safety in the UK and the US, so OSHA statistics are not likely to be a relevant benchmark.

The current edition of the IOSH learned journal PPHS includes a couple of papers about leading indicators used for monitoring construction sector health management on the London Olympics sites, and some ideas on how they might be adapted for other situations. A key idea is to manage 'health like safety', rather than expecting that only OH physicians and nurses have a leading role.