You ought to take a look at the reviews of the Panasonic and Sony systems you were considering. Here are just a few excerpts. Each line is from a different user's review:
Panasonic
"We ordered two different models unfortunately the first one didn't work. The second CD player work fo 10 minutes"
"Sound quality is crap"
"Don't waste your money. Rubbish, even for a midi"
"Very cheap and nasty cds either jumped or was running fast"
"I found I couldn't skip more than one or two tracks - if I did it stopped playing completely and I either had to eject and reinsert the CD, or turn the unit off and on again"
"...attempt to play a CDR. It didn't work and I thought perhaps that it may have been due to it being a CDR so tried a further two factory recorded discs. Responses NO PLAY and NO DISC"
Sony
"Bought this to play my CD,s problem being it will not play any of them not even sony label bands, total rubbish"
"Awful product! Cheap, lightweight feel to it. Sound quality below average."
"...had 2 CDs freeze while playing, these CDs have no scratches whatsoever and they play on all other CD players"
"took ages to load and read CD and the CD tray action was noisy and clunky"
"Played one track from a CD, let out a high pitched noise and stopped playing. Will not play or eject the CD"
"It's a cd player that does not play cd's! Avoid!"
"...the sound quality is awful. ... There is no presence or clarity whatsoever, just annoying vibration."
"now failing to play (CDs) at all - occasionally showing the total track length and track count, but usually just displaying 'no disc'."
End-user reviews tend to be something of a mixed bag. Positive and negative reviews need to be taken with a pinch of salt. I understand you reading the reviews and expressing a bit of caution. However, I also think you need to take a look at the bigger picture.
No matter what piece of consumer electronics one buys, there will always be product failures. The industry average is 2-4% depending on the type of tech' and -
to some degree - how close it is to the bottom or the top of the price range of its peer group. If you're looking for perfection both out of the box and for any length of time then you'd better give up with consumer electronics and start buying flawless diamonds.
You're here because your existing stereo is broken. Doing a repair probably isn't cost-effective, so you're now looking at a replacement, but you have certain restrictions such as size, function, cost, being new, and the technical requirement of driving a set of high Ohm (large-ish?) speakers.
The first product you listed won't meet your needs. We saved you from a lot of disappointment and wasted time with that one. Need I remind you also that you were ready to push the buy button on it, and not once did you question its poor reviews? For your next choice you doubled the budget. That was sensible. But it has some (IMO) some serious technical shortcomings. Yet again though, you never made a peep about the reviews.
I have shown you a product that appears to fit all your specific requirements, and is near-as-damn-it bang on budget, and that can drive those speakers better than anything else under £300. Now suddenly you're picking holes and coming up with excuses. In the psychology of sales we call that behaviour
unreasonable objections. It's a delaying tactic. It shows that the customer's needs have been met but they're fighting saying yes because it means admitting that their quest is at an end is scarier to them than pretending that no solution is good enough.
The Denon D-M41DAB isn't flawless. No product is, and certainly no product is for just a couple of hundred quid. However, it does have better reviews than the Sony.
What I would suggest is you arrange to demo the Denon at a Richer Sounds store. Take along some of your home-recorded CD-Rs and try them in the system.