Requirements for a Fiancee Visa

[Terpe]

..... I have been told - admittedly, by word of mouth only - that besides needing an income of £18600 per annum, I need a reasonable amount of money in the Bank. Is there any truth in this or not?

Harry, as others have said there's no truth in that at all.

As an aside, for savings to be used in support of Fiancée/Spouse/Partner the UKVI will only consider amounts above £16k

If you haven't already done so I'd suggest reviewing the application form and the Financial Requirement.
Anything you're not 100% sure on just ask here. Plenty of members been there and done it.