I think flashbacks like that can work well, as long as the reader doesn't get confused about the sequence of events that the flashbacks present (if sequence is important). It's also important to allow the reader to tell when they are reading a flashback, and when they are reading present-time events. I've come across books where the transitions between such passages aren't clear, and where you have to read on a little before you realise where you are, chronologically.

My flashbacks are dated so no problem there.

"My flashbacks are dated so no problem there."

Although don't forget that an awful lot of readers actually don't read headings, chapter title, datelines and stuff. I know, because, try as I will, I don't - my eye shoots straight over them to get on with the story. I've trained myself deliberately to read them, for the purposes of teaching and doing appraisals, but it still doesn't come naturally.

The thing is, even if readers do read dates or whatever, we have to have remembered the previous date, to know how it relates to this one and then understand the significance of how much time has passed, or that we've shot backwards, or whatever. Essentially, if a reader has to stop and work it out - let alone flip back in the book to remind themselves of other dates and places - then the writer has failed. A date on its own means nothing - unless maybe it's a date that is famous in history. Even then, its significance for the story can't flower properly if the reader doesn't have another anchor from before, to relate it to. Places work better, because they log more easily in the head for most of us, though if it's all obscure villages, not "London" followed by "Paris", it may not work all that well.

My rule of thumb is that you need two hand-holds for the reader in the opening line or three after every abrupt switch of time or place. One might be a dateline or some such, but the other hand-hold had better be something which operates on us intuitively, by being embedded in the actual narrative: voice, names, material facts, perhaps a switch of tense.

This blog-post on different ways of getting from one scene to the next also applies to moving to and fro in time  and place:

http://emmadarwin.typepad.com/thisitchofwriting/2015/01/getting-from-one-scene-to-the-next.html

And this is about different ways of handling backstory and bits of the past:

http://emmadarwin.typepad.com/thisitchofwriting/2011/10/flashing-slipping-and-mixing-things-up.html

PS - I suspect the problem's even worse with ebooks, since "flipping back" is almost impossible.

I understand what you mean about not reading the title, date etc and yes I have occasionally flipped back to find out whats happening (I find it no problem with ebooks) but my flash backs are preceded by something that warns you. here's an example from my story 'Luck'

.......luck's played a big part in my life. The earliest memories I had were about luck - bad luck though. The night my dad died in fact.

The Threpenny Bit.
 Early June 1966
I am three years old. Me and mum are going to visit my Nanny and Grandad. Nanny and Grandad are my mummy’s parents. They live in a city called Salford. We live in Manchester which is next door my mum says....

Other flashbacks come up in conversation. Initially I was going to alternate chapters bringing the flashbacks up to date then continuing. I could still do this. When I have completed my book I will try both and let 'test readers' decide which they like.
 

Yes, exactly - what I call "handholds". Voice is the most intuitive handhold of all, so even without the dateline and title, we'd know where we are.