‘British spies were first to spot Trump team’s links with Russia’:-
https://www.theguardian.com/uk-news/2017/apr/13/british-spies-first-to-spot-trump-team-links-russia
&
GCHQ ‘told US security services about meetings between Donald Trump’s team and Russia’:-
&
‘Ex-MI6 chief says Donald Trump may have borrowed money from Russia to keep his empire afloat’:-
http://www.mirror.co.uk/news/politics/ex-mi6-chief-says-donald-10217616
Why did they deny it vehemently when the story first broke but now they own up to it?
Sorry mate - could you be a little more specific on what they denied - and what they are now ‘owning up to’?