Exercise 1: £15,000 Cash ISA Plus £8,000 Stocks & Shares ISA — Possible Solution
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This is not allowed. The real UK ISA annual allowance is £20,000
total, shared across every ISA type combined - it is not a separate
£20,000 for each individual type. £15,000 into a Cash ISA plus £8,000
into a Stocks & Shares ISA would total £23,000 of new subscriptions in
the same tax year, which is £3,000 over the real combined £20,000
limit.

The person could still contribute to both ISA types in the same tax
year - that part is genuinely allowed, since the £20,000 allowance can
be split across different ISA types however the saver chooses - but
the combined total across all of them cannot exceed £20,000. In this
case, the remaining real headroom after the £15,000 Cash ISA
contribution is only £5,000, not the full £8,000 they're trying to add
to the Stocks & Shares ISA.

ANSWER: This is not allowed, because £15,000 plus £8,000 totals
£23,000, exceeding the real combined £20,000 ISA allowance for the tax
year. Splitting contributions across different ISA types is genuinely
allowed, but the total across all of them must stay within £20,000 -
here, only £5,000 of additional room remains after the £15,000 Cash
ISA contribution, not the full £8,000 being attempted.

WHY THIS WORKS AS AN ANSWER
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This correctly applies the chapter's own real, combined (not
per-type) £20,000 figure to the specific numbers given, and clarifies
that splitting across types is allowed while exceeding the combined
total is not.