DFC
The URL you give doesn't appear to point anywhere useful.
If you can find a document which explains all the cryptic error messages which the CFMU website returns and how to get around them (without having to purchase every country's SRD and other publications) that would be useful. But even the CFMU support team failed to point me to anything like that.
Personally I prefer
http://rfinder.asalink.net/free/
I don't doubt for a moment that some OCAS routes pass CFMU. But this is far from being able to stick any old Class G/D route (such as are routinely flown on the IMC Rating) and have it accepted.
I know you know all the documents backwards so probably won't like this but if you send such an FP to Homebriefing, and they file it via Eurocontrol (which is completely correct for an IFR FP) it will go to London Control (or some other UK airways sector authority) who will be
completely uninterested in somebody flying via SAM at 2000ft... so when the poor sod turns up at the Solent CAS and calls them up they will say G-XXXX WHO are you??