Can't help with the websites, but there are some in any decent almanac. What I want to know, however, is why are the published copies of tidal streams so expensive? Seems that anything intended to make nav. safer and easier has to come with a mega £ price ticket. Don't mind anyone making a fair profit, but can (almost) understand why the likes of Eric navigate with an AA atlas!!
Relying on an Almanac for tidal flow is renting not buying.
You have to replace the almanac every year. (Plus the diags are often smaller and less detailed than the real thing. And they're printed on thin paper so you can't write and erase on them much. Plus at the end of the year you lose any notes and observations you've made)
Buy a tidal atlas and it's yours for life. Cost of acquisition may be high, but cost of ownwership isn't.
Get a tidal atlas, have each page laminated and ring bound.
Put a strip of scotch (not sello-) tape at the top of each page - you can write on and erase this using a 2b pencil
I have been using the same series of tidal atlases for about 12 years (and I bought those at a boat jumble for £1 each!
They are still like new