TS-451A UPS advice needed

[MrJeff]

I'm a first-time buyer looking for an Uninterruptible Power Supply to use with my TS-451A, and I was wondering whether anyone here would be kind enough to point me in the right direction. The NAS is being used in my home mostly as a media server, and is the only device that will be using the UPS. As it stands, literally the only thing I'm hoping to achieve is that, in the event of a power cut, the NAS will shut itself down safely. That's it. So, my questions are:

1) Are there any other features a complete novice like myself should be looking for but clearly hasn't thought of?
2) What sort of capacity would you go for in the same position?
3) Should I only consider what's on the official QNAP compatibility list (https://www.qnap.com/en-us/compatibilit ... category=9), or are there other options?

I'm in the UK, by the way. Any advice will be greatly appreciated.

[MrJeff]

No takers? Okay, change of tack...

I'm strongly considering going for an APC Back-UPS ES 550 (https://www.amazon.co.uk/APC-Back-UPS-5 ... 002RX6NY0/). Has anyone here used one of these? Would you recommend it? Can I expect it to play nicely with my QNAP NAS? Anything else I should know about before I take the plunge?

[dolbyman]

I have the Back-UPS ES 550 and it works just fine ...

has enough juice to keep my NAS and networking equipment running for 30min and then shuts the NAS down gracefully (networking equipment continues to work for 10-15 min after)

[MrJeff]

I have the Back-UPS ES 550 and it works just fine ...

has enough juice to keep my NAS and networking equipment running for 30min and then shuts the NAS down gracefully (networking equipment continues to work for 10-15 min after)

Exactly the sort of info I was hoping for - thank you very much indeed.