UCITS stands for Undertakings for Collective Investment in Transferable Securities

It's illegal

An Enterprise Investment Scheme is when there are a bunch of tax reliefs that encourage investments in small companies carrying on a qualifying for trade in the UK. The purpose is to offer compensation for the risk of not being listed on a stock exchange.

An index fund or index tracker is a collective investment scheme (usually a mutual fund or exchange-traded fund) that aims to replicate the movements of an index of a specific financial market, or a set of rules of ownership that are held constant, regardless of market conditions.

Yes- its just a type of high yield investment program.