Okay, that's weird - I wrote a whole reply to your question above and posted it through Tapatalk a few minutes ago, and it doesn't appear to have been sent at all!
@ksand24 I have read on the forum that no one should enter the UK via Ireland. I'm assuming that's to do with Brexit. When my husband and I went to visit Dublin back in April we had to go through customs flying from Glasgow to Dublin but then when we flew back from Dublin to Glasgow we did not have to go through customs. So my question is… Is it OK to enter the UK via Paris or Amsterdam or some other EU city as long as it’s not in Ireland?
It has nothing to do with Brexit. It's because the UK and Ireland form part of the Common Travel Area (CTA) and therefore there are no immigration controls between the two.
When you first enter the UK on your visa, it needs to be stamped by UK immigration to 'activate' it and to show what date you entered the UK, so you can prove when you qualify to apply for FLR(M) and ILR, and also to be allowed to pick up your BRP.
However, if you enter through Ireland, you will only go through Irish immigration and not UK immigration... which means your passport will not be stamped (it is illegal for UK immigration to stamp it if you entered through Ireland), which means you won't be able to get your BRP...which would then mean you'd have to leave the UK again right away and enter through another country (i.e. a channel hop to France) to get the stamp in your passport.
Therefore, you must make sure you do not enter through Ireland on your first entry with the spousal visa (other entries after that are fine). You can enter through ANY other country in the world, except Ireland.