The suggestion that OP should be grateful they weren't TIRed demonstrates, yet again, just how much is wrong with the attitude to customer service the rail industry has.
I hardly think it’s such a poor attitude to expect the passenger to follow the rules which has quite clearly not been done (perhaps with justifiable reason, perhaps without).
The textbook approach is that if the passenger has not filled in the date, you should cross out an unusued box, and fill in the next available box yourself. If you cross out the last unused box then the passenger is treated as if they boarded without a valid ticket because they can't date a box for that day (they now have none left). I've never enforced this rule but know many who have.
so the textbook penalty for not dating a box before you start your journey is to lose a day on your rover. Is that just your operator or is this a general rule?
personally I consider this fair if the passenger has no reasonable excuse for not doing so, so as always discretion appears to be key here
So if everyone can use a pen to the same exact flawless standard and legability and write things 100% perfect all of the time, why do we have computers to do most of the work nowadays?
I think it is equally perverse to expect humans not to make simple mistakes and then jump on them with accusations of fraud to get out of paying for delays.
I also don't see why I or anyone else should have to bring a pen just to dance to the railways tune because their ticketing requires validation (in this case with a pens) and they don't provide the facilities to do so (If they did they would most likely provide pens that aren't fit for purpose and can then be used to accuse wrongdoing). I have never in recent years brought a pen for validating a ticket and don't intend to start now.
I don’t think it is worth trying to answer why we have computers, i’ll use the excuse that it would be too far off topic. We have rules that we are expected to follow, some of them are outdated, as are the principals, concepts and scenarios they relate to, but that doesn’t change them. I think if people don’t want to carry a pen with them that’s fine, but this doesn’t change the rules. People who are happy to break them don’t really concern me, but they shouldn’t expect to receive sympathy if they are penalised for not following the rules. Part of the issue tends to be the attitude test. To politely ask a guard, or someone in a ticket office, a shop, or just a person on the street or platform (appreciate things are different currently) to borrow a pen is perfectly acceptable (and not everyone is confident in asking a random person for this, so they may want to limit this for the guard or other staff member, or consider carrying a pen). But to categorically say you’re not going to fill in date boxes because you won’t carry a pen is likely to end up in a thread on here which I would not like to see. Back on topic (sorry), the key that has been touched on here is the OP who does contribute to other topics hasn’t returned as yet, but also, they chose not to explain any of the things that should seem obvious in the initial posts. It’s clear that 29 1 was written in the month of part 1 and the day of part 2, as a genuine error either by a guard or by them. They’re not prepared to explain further and again, it seems strange and suspicious despite there being no indication whatsoever of any genuine attempt at fraud. I don’t think we can get any further unless the op explains more.