1. The term VIP - as I understand it - ONLY applies to proofs struck by the Mint in years where there wasn't a regular proof issue. They were, I understand, presented to VIP visitors to the Mint and are very rare. The term therefore applies to the reason for striking, not the coin itself.
2. That special issue of 1977 crown may well be the exception to the above - a genuine VIP issue of a coin that was issued in large quantities, and with a special case, greater weight. (The case on its own proves nothing, but the greater weight is notable). More provenance would be desirable, but that would probably ensure the coin sold for more than £1000, especially if it was issued to a minor Royal.