If you are a basic rate taxpayer, investing a modest amount, there's no harm is using an ISA, but actually no immediate benefit.
Share dividends ar taxed at 10% before you gt them, and your ISA can't claim the tax back (neither can you) so there will be no saving there, even if you are not a taxpayer.
Capital Gains tax is unlikely to affect you, so no saving there.
It is terrribly important to use a scheme with very low fees and expenses, otherwise more of the gains will be going into other people's pockets than into yours. Hence avoid "structured" or "guaranteed" schemes, since it will be you paying for the structure and the guarantee.
Equally you don't want a scheme that an IFA will make (your) money out of. So an IFA won't want to sell you such a scheme. So an IFA is no use to you.
I'd suggest the savings scheme of a simple and unadventurous Investment Trust but no doubt there will be other ideas.
You want all the income to be reinvested at low cost. You don't want anyone to earn any commission out of your money.
Any equity-linked investment runs the risk that teh day you want to take your money oput, the market may have fallen into a trough so prices will be low.