The Romans

In his writings Caesar mentioned Ireland in relation to Britain geographically and his descriptions were pretty good of the area in general.

The island is triangular, with one side facing Gaul. One corner of this side, on the coast of Kent, is the landing-place for nearly all the ships from Gaul, and points east; the lower corner points south. The length of this side is about 475 miles. Another side faces west, towards Spain. In this direction is Ireland, which is supposed to be half the size of Britain, and lies at the same distance from it as Gaul. Midway across is the Isle of man, and it is believed that there are also a number of smaller islands, in which according to some writers there is a month of perpetual darkness at the winter solstice. Our enquiries on this subject were always fruitless, but we found by accurate measurements with a water-clock that the nights are shorter than on the continent.”

It shows he was a practical lad with his note of not believing stories without evidence. He also mentions his surprise at how populous Britain was. He reckoned it was among the most populous places in Europe he'd visited, which is a surprise

One of the later Roman governers(whose name escapes I'm afraid) mused on a plan to invade or how he would do it anyway. He reckoned (again AFAIR) that he'd only need two legions tops. His plan was to be a pincer movement. One fleet would sail from Wales while another would sail from Spain. It was a common notion at the time that Ireland lay off the coast of Spain as much as Britain. Great engineers they were, cartographers they were not In fairness most writers thought similarly. If he had taken up that plan it would likely fail. The spanish pincer guys would have been filled with blokes shouting "are we there yet?" in Greek.:D

The Irish sea would have been a bigger barrier than the English channel. They could have invaded from Ulster, but that would have required a stable presence in Scotland and we know how that enterprise fared... Plus stretched as their supply lines were against the Scots and Welsh quadruple that in an Irish invasion.

Then you have to look at what classical writers thought of the place. Strabo reckoned we were savages living in perpetual winter(AFAIR he also noted there were no snakes). Tacitus(like Caesar) thought it was like England only smaller with milder winters, but the grazing was better.

So I'd reckon it was too much bother for an unknown return. Their supply lines would be very long and they already had their hands full with Celtic brits, never mind the Gauls on mainland Europe. Maybe if they thought the place was stuffed with gold or whatever they may have bothered? I'd still reckon they'd have had their hands full. I'd be fairly sure they had a bit of a sniff through trading enterprises and just felt it wasn't worth it. Maybe if they'd stayed on in Britain? The embarrassments they suffered at the hands of the Scots probably preyed on their minds, so the notion of doing all that even further away and with a wider sea at their backs probably gave rise to a large feeling of "meh".

In the end it seems it was better they hadn't as the explosion of civilisation that kicked off on this island after Rome fell may not have happened.

Hmmm. I dunno, a couple look too crisp to me. Plus even if real, Roman coins are two a penny(no pun). I got a bag of 40 odd of them for 80 sterling a few years back. All found in the UK.

With these considering the claim context is everything. Even if real how do we know they came from that area? Handy to have an enthusiast have a look. If they're from different periods then more likely to be fake or planted IMHO. If too early probably a given. If they're all from the same period and it's late it might be part of a lost "hoard".