I am failing to see where there is a problem. A Class 1 OML is generally equivalent to an unrestricted Class 2 (with a few exceptions as above.)
With a Class 2, one is operating as a PPL and as an FI, can instruct ab initio.
However to instruct a CPL course the FI needs to hold the same licence and therefore a Class 1. If this is restricted to OML, generally there is not a problem as one's student is post solo xcountry. The only difficulty comes with CPL integrated courses. The tables in CAP 804 are a complete mess as they have been cut and pasted from JARs and have not caught up with the fact that under EASA only a PPL is required for remunerated PPL instruction.