I'd say there might be no problem with the american tapes. More and more vcrs can handle both formats with ease. Have you used tapes from the US before?
However, if the vcr is older and has never played US tapes there could be a risk of the tapes not working.
The vcr booklet might tell you.
Since you are in England, and you remember Hunter being on over here, maybe you can answer a couple of questions for me. Did ITV show Season Two round 1988? On Saturday evenings, in the pretty much the same slot they ran Season One? I thought for years that they skipped S2 completely, and then last week I read an episode description for "Case X" and had a sudden flashback to seeing it. And the more I thought the more I remembered, and I seem to think I saw it round the time my parents moved house, which would place it at 1988. After moving house we had no ITV for a while, and I'm now wondering if Hunter was on there for a few weeks?
Of course, maybe your memory of Hunter doesn't go back that far. Maybe you're a fan from the late-night screenings a few years back...