Sky/yahoo issues on ipad

Assuming that you are using the native Mail App, your incoming mail server settings are here - as are your outgoing mail server settings:

Settings > Passwords & Accounts > [Your email account] > Account > [Incoming Mail Server]

If you initially set-up email using the wizard (selecting Yahoo), it may be necessary to delete your email account from your iPad - and re-add the account manually. Doing so will provide full manual control of your settings.

Clearly I have no idea what information you have been given - or its accuracy, so lets assume some healthy scepticism in this regard.

I note from a quick skim of the linked guide that Sky use App-specifc passwords when manually configuring email, so you'll need to create the password for this explicit setup. Here is the relevant passage from the linked guide:

To help protect your email account, instead of your usual email password you might need to generate a unique app password to use on your iPhone or iPad Mail app. 

You'll only need to use this password once for the initial setup. After then, you'll stay signed in automatically.

Generate an app password >

If setting-up manually, you don’t use the wizard. Instead you should select “Other” - and manually enter your email account settings.

The manual method is still semi-intelligent, in that it will select the most likely settings for you (based upon the email address that you enter) - however, you should still be able to refine the account settings after the account setup is complete.

I presume you've seen and are working from this?

https://www.sky.com/help/articles/getting-started-with-sky-yahoo-mail-v1

As you're setting-up manually, might need to obtain the appropriate server settings. At the very least, you'll obviously need your account credentials.

“I assume that we’ve reached the end of the road with my problem then!”

From this comment, I infer that you are seeking an outlet for your evident frustration.

I and other contributors within the Apple Support Communities are not on the payroll of Apple, Sky, or anyone else; we are not paid for the user-to-user technical support that we provide to those who seek assistance.  We are all end-user customers of Apple products, just like you.  Where we are able, we try to share the benefit of our knowledge and expertise - hopefully finding resolution to a problem.

Regrettably, it appears that nobody else here has provided any additional suggestions beyond that I’ve already provided.

Insofar as I have no way of replicating your explicit problem with provider-specific steps to set-up email for your Sky/Yahoo email account - beyond the comprehensive information from Sky to which I have already provided links (which I had to find on research for your benefit) - I regret that I am unable to provide additional assistance.

What is perhaps disappointing (but on the basis of their reputation, is not overly surprising) is that Sky appear disinterested in providing effective technical support to you, their paying customer.  It may be in your best interest to find an email provider more suited to your needs as, even if you are wedded to a service contract for their media services (this being their core business), nobody is forcing you to rely upon a sub-par email service. Sky have clearly farmed-out email to a third-party provider (Yahoo in this instance).

Have you tried seeking help from Sky’s own Support Forums (“official” or otherwise)?  You are more likely to find assistance in overcoming difficulties you have with Sky services from others who may share similar problems.

Whilst not managing on this occasion to find a resolution for you, I hope my contribution has been helpful.