I heard being assigned both roles was fairly popular in some organisations, does no one have any experience with this then?

Yes I also have duel? roles and have put ISO9001 & ISO14001 into two companies and 18001 into one. To be honest I only went on an internal auditor course which was more about auditing than the standard. I had a copy of the standard and read through it a few times. It is not just a list of things to do, as some of the clauses impact on others ie Document control. I then went and asked every manager in the company what they and their teams did, I made copious notes. I then copied the standard into a spreadsheet to create a gap analysis tool. I went through each clause and thought about what I had been told and how that might satisfy the requirements of the clauses. I was then just left with the gaps to sort. Do not try and reinvent the wheel, if the company does something that meets the requirement of the clause then all good. I bet your company has a process of what to do if you screw up - well that is a NCR procedure etc, just write it down. I then wrote up the main stepping stones of each managers /director notes into flow chart type procedures, ensuring I covered the specific parts of the standard where appropriate (used their terminology a bit too). I tried to ensure that outputs from one procedure were inputs to another. Procedures given back to Managers / Directors and asked is this correct. They all became owners of their own procedures, which could not change unless I ok’ed it (so nothing required by standard was removed). So – Buy Standard – Read and again – find out about all elements of company – do gap analysis – put in place anything missing - write it down and link together as appropriate - Audit yourself ( ie company). Part with shed loads of money (company not you) on external auditors. Easy Chris