If Swala does decide to list on the London Stock Exchange, given that it will own shares in a producing asset, it may be able to be listed on the LSE Main Market instead of AIM.
Another Tanzania oil and gas company, Aminex is listed on the main market with a market cap 110 m pounds
http://www.londonstockexchange.com/...ry/company-summary/IE0003073255IEGBXSSQ3.html