Sound ID: Is this a Chaffinch or a Blue Tit ?

Question

Hey, this should be a pretty easy one to answer, but it's been causing me a lot of confusion. 
 
 This audio contains a blue tit song: https://macaulaylibrary.org/asset/304254101 
 
 What I'm not sure about are the two initial "wheep wheep!" - is that the blue tit, or is it a chaffinch in the background? 
 
 To add to the confusion, I've definitely been hearing that "wheep wheep!" alongside blue tit song/calls when I'm out and about, and I can't tell if I'm hearing both Chaffinch and Blue tit, or just blue tits.

leifvester · Accepted Answer

I finally worked this one out! Got a recording myself this morning (excuse the traffic background noise): ebird.org/.../S150538156 
 
As confirmed by Merlin, it's not a Blue Tit nor Chaffinch - it's a Great Tit! 
 
That's quite a tricky one, and I'm quite sure I've been under counting Great Tits all year in my checklists because of this - oops! Well you live and learn. 
 
It does sound very similar to the Chaffinch call: macaulaylibrary.org/.../133259551 
 
The difference I think is that the Chaffinch has a sharper call than the Great Tit; still going to be a tough one going forward. The context will matter a lot, trying to hear additional sounds / get a visual.