I owned stock in a U.S. OTCBB listed company that listed on the AIM. The way they did it was completely transparent to investors. They opened trading on the AIM and here in the U.S. our shares were converted to ADR's (same thing really).
A R/S is not necessary. Floating new shares is not necessary. It's up to management whether they want to do either of those. I don't see a R/S because ERHE's assets justify the OS (once proven). Given the proximity of drilling floating new shares now would be insanity and grounds for immediate termination of the bonehead that thought of it.
IMO, they will list on the AIM after first oil. They will float new shares after many successful wells. I'll guess AIM in 2010 and flost new shares in 2011+.
wc, there probably won't be any switching of exchanges for now. Look towards the AIM with some kind of deal, acquisition or partnership, and an IPO for a new listing of an ERHC company.
Anyhow, that's how the announcement at the meeting about a new VP and the PR today reads to me.