There will be a minimum issue of stock on the aim. The comapny...

There will be a minimum issue of stock on the aim. The comapny will have requirement to to maintain a float or sorts. Companies usually do this by transferring some directors stock to the london broker. There may be arbitrage brokers working on it only if the liquidity or market is there. They can use this stock to make sure stock settles on time and no fails then buy the stock through arb to get it back and replace what was used. On recent volume there should be but then you get too many on the arb and they loose interest.

Should be enough liquidity on aim from insto, there's always one insto seller!