The answer is yes but!
The one they can definitely do, assuming it isn't at full capacity, is full LLU through Opal Wholesale. This isn't shown on their website yet, so you need to contact them if you are interested.
Full LLU is where the supplier (Opal) also take your phone line off BT Openreach Wholesale Line Rental, like TalkTalk do and Sky do if you have Sky Line Rental (not just Sky Talk). This is fine until you want to migrate back out, as you have to get the line back onto Wholesale Line Rental (or to Sky perhaps) before you can go to another ISP.
A few ISPs can arrange a simultaneous transfer back but the selection of well-known ones isn't huge and the process is unreliable. You therefore run a risk of being without broadband for several days, or possibly a week or more.
There is a possibility that Oswestry has been enabled by C & W. It was listed in April as to be done, but isn't listed in August. So maybe it has been done, or maybe dropped off the radar.
That would be partial LLU like O2/Be and others, so no problem with the line. It is the xilo/uno Pro 16 service, which despite its name is not limited to 16Mbps if your line can go faster. Again the only way to find out is to ask, though in this case I think they have an online checker you could try.
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