@samiebon1 Here are the photos as requested: the distance between front grill and opposite wall is 99 cm. (105 cm. From outer case to wall) The left hand end of unit is some 150 cm. from boundary.As you may see, there are plenty of doors and windows plus drains to consider! Regards, Toodles.

Photos too large a file I think; will send 3 and then 2 more after.

And here are the other 2…

And space behind pump is 31 cm. Regards, Toodles.

Sorry, 33 cm’s. ! Toodles.

@samiebon1 alleyways aren't always a definitive no-go; many act as wind tunnels, effectively "recycling" air, though it's uncertain if your specific alley would be fully conducive to that. You could do one of those smoke tests to see how effectively the air moves and circulates. Here's one that Heat Pump Newbie from the forums did to test their air movement:

Gary also brings up an important consideration regarding the 1-meter from boundary permitted development requirement. This is a major headache.

Observing situations like these really highlights the complexities of ASHP installations in residential areas. It prompts the question of why district heating, considered on a street-by-street basis, isn't taken more seriously by councils. This approach could address numerous challenges, especially in terraced housing rows.

@gary I'm fully expecting to have to go through planning permission for it, a faff but hopefully ok. One of the surveyors did a sound pressure calc given the setting and I think it was only 2dB over permitted level (whatever that means!).

@toodles brilliant! Thank you Toodles, really appreciate that. Looks a similar-ish setting (wall lay out that is) though a tad more constrained in my case.

Lovely day for photos, have a great day wherever you are!

@editor my hope is that meeting the clearances of the manufactures installation would give the rated SCOP, though may be wishful thinking.

I saw the HeatGeek video testing with smoke pellets and varying clearances which made me think that even my slightly more constrained area would work, thought again appreciate it's less than ideal layout.

I'd be really keen to try see if there are any organisations local to Manchester which could use this kind of layout as a test bed because it's such a common form. Thanks Mars!

@samiebon1 Our Daikin does reach the COP but I haven’t gone the extra mile to ascertain the SCOP; at present, these sultry conditions provide a COP of 5+ and a few weeks back in cooler circumstances, we were seeing 3.75 - 4.25 ish. Regards, Toodles.

@toodles 😯 5+ 😯 I barely get much above 2'5 even in this current mild weather.  Must get a Heat Geek in!

@morgan I was getting 4.5 in early February when Daikin service agent came to do the first annual service. I was informed at the end of the service, that the main pump ran with very low resistance, the magnetic filter had just a very fine line of black inside and that he was impressed with the quality of the installation too. We do have an LLH and this would appear to be running quite efficiently (I have reported this in detail elsewhere on the forum). I have a Homely smart controller and their technical support are also impressed with the running of the system from the data they are receiving. It is worth noting that we run our system to produce 22.5 degrees C throughout our 4 bedroomed house 24/7. Regards, a very contented Toodles. 😉