I have compared Arcam with Anthem, but my Anthem preference was for the Statement D2v and I have not considered the AVM50v. The D2v, like the D2 is an ugly mess of buttons and it doesn't have LAN connectivity.
At the time I bought my AV9, it was a shoot-out with the D2, the AV9 won on phono support (MM and MC) and looks, with sound quality (D2's built-in tuner ignored and LP not testable) a tie. You can find my comparison on the Anthem owner's forum. The AV888 dropped MC support

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Although Anthem is new in UK, it's not new in Europe, let alone in Canada. The biggest problem with Anthem in UK is the fantasy price - it is way over what it costs elsewhere. Over here the D2v is a little more expensive than the AV888, but the Arcam also costs more than a UK - UK VAT x exchange rate + CH VAT. so the comparison is easier and if I had the cash, I'd buy the D2v rather than AV888 (MC needing external support either way). Whether the difference is worth what the UK wants is another question.
BTW, the Anthem P2+P5 is rather more powerful than the P7/P777, although whether you need that power is another question - I didn't. It's also better at horrible loads, which may become important if I replace the front Quads with Martin Logans.
I would recommend your carrying out an A/B comparison.