Russia's story has so many plot holes it should be a Hollywood movie.
"Yea...we flew 1000s of miles on fake passports to visit one Cathedral in a very un-touristy area, then flew home a day later without our luggage. On the same day an ex-Russian spy was poisoned by Russian nerve agent. Perfectly normal, what's the problem".
It would look less suspect if they said nothing. But Putin said they were going to talk to the press, so they had to wing it lol
The story is a bit odd - the defence of it was a women's perfume bottle seems a bit odd and raised as a deflection as all they'd need to say was it was for a gift for a women friend/relative or something (maybe need to be a bit prepared for the unlikely chance the officer would want to know the women's details) and off they'd go without it looking odd at all - pretty much everyone understands buying perfume for a girlfriend (or "girlfriend"), etc.
On the other hand it can be quite strange (to us) what people visit the UK for tourist wise - some things seem fascinating to those of other cultures that we wouldn't even give a second thought - there are Chinese for instance who will fly in from 1000s of miles away to spend just a day visiting Kidlington before leaving again - though presumably they take their luggage with them.