I think that Steve meant to say that the pattern/plug will flex around the wheel arch area in order to allow it to come out of the resultant mould. It's hard to judge from the picture, but it looks like the only potential locking area might be the return edges on the arches, if you plan to incorporate some?

On such a large part the only concerns I can really see are all the detailed contours at the front section and getting a good release, especially on a new mould. It's possible that you might get some breakage on the pattern or the mould surface getting it out. Not certain if you plan to make the final part in GRP or carbon, or by what method but building in, at least, one parting line might help you get a decent part first time even if it involves a bit of work to tidy-up the join

Yes, the problem I see, is that the mould should flex around the lips of the wheel arches. A mould as flexible as that will result in inaccurate parts.

I would like to make a one piece mould (less work) of the front of my Elan so I can make a one piece flip front. The bonnet will be fitted and blended in prior to making the mould. I can't see any locks. The mould should flex around the wheel arch lips. Can anyone see any problems?