DUB-Edinburgh help with flights?
 

Simple - If you can't downsize your bags -- then pay the extra they charge to check a bag or pay the premium fares that allow larger cabin bags.

>>Neither of these will be allowed on the planes to Edinburgh<<

Does not mean they are not 'allowed' on the planes but are not allowed for free in the cabin.

Several nonstops daily on Aer Lingus, or numerous one-stops on BA via London, both around US$150, but the BEST deal (amazing, actually) is a "fifth freedom" flight on Hainan Airlines (a first-rate Chinese carrier) that flies DUB-EDI a couple of times a week using Boeing 787 wide-bodies for €61.47 one way with one free checked bag. Bookable on Expedia.

("Fifth freedom" flights are those operated by carriers flying between two locations, neither of which are in the airline's home country. Other examples include Cathay Pacific between JFK and Vancouver, Singapore Airlines between LA and Tokyo, and Latam between Madrid and Frankfurt, among many.)

I think you've misread Ryanair's bag rules a little bit.

One small item (40x25x20) is always included.
This size is what other airlines often call the additional "personal item".

The regular cabin luggage can be as large as 55x40x20 and will travel in the cabin only for an extra fee.
The extra fee will be a whopping (just kidding) €6 - which will also give you priority boarding.
This priority option for €6 also includes the small "personal item".

So for €6 per person, you will get:
1) priority boarding,
2) the small item 40x25x20,
3) the regular cabin bag 55x40x20

You can add this "priority" feature when you book. Or later when you check-in and get your boarding pass (BEFORE you get to the airport).

No, that's a different version of the 787. Hainan flies 787- 9s, the Singapore planes are 787-10s.

Yes. Like all modern planes, the 787 has several variations. These include different dimensions, seating capacities, engines, flight range capabilities... The term "Dreamliner" is a marketing device, nothing more. Like the current issue with the 737Max - it's that variation of the 737 that's currently grounded, not the thousands of other 737 models, like the 737-800, -900 etc.

Singapore's 787-10s are suspected of having some troubles with the specific Rolls-Royce Trent engines used on those planes. Singapore has NOT grounded its other 787s (-8s and -9s) that use other engines. https://simpleflying.com/singapore-a...engine-issues/

Choose the standard cheapest fare with only the one small personal item, when you progress to the next screen, you are offered the option of adding the regular cabin luggage. If its EUR20 each way, you may have selected the Plus option with checked luggage.

You need the middle option, it is not a standard €6 price, the price varies by date and flight taken, it is different on the way out to the return flight.

The option with checked luggage does not have priority boarding, not that that makes any difference IME, not on Ryanair anyway.