Invite ?, Doesn't it come through the letterbox with a little push ? - cue jokes that someone will get banned for ..........
https://www.screwfix.com/p/d-line-multi-cable-cover-light-duty-black-1-8m/9345f I think it's safe to say this is the most serious suggestion you will get. Without chasing floor or coming from ceiling is basically your only choice.
I often use rechargeable power banks to provide small amounts of power for lighting etc. In the back of the van I use a Dewalt 18v USB adapter to power led lighting and also a (temperamental) floodlight. Had a little digital radio on it too. Not sure it would have quite have the guts to run a dishwasher and a hob though! At the moment I have a RAVPower 16watt fold out solar panel on the dash of the van all day. I use it to charge my phone and bluetooth earpieces. It works superbly even on cloudy days. It has two outputs so usually I have my 10000mh RAVPower powerbank charging up too. That will charge from flat in a couple of days.
I have a £100 solar panel on my allotment. It runs my hot water van wash, lights, USB power and via a 2000w inverter two 13 amp sockets - perfect Although I would love this to come to the UK - you put 4 x 54v batteries into it and you get 220v out and its virtually silent.
A solar panel won’t work. You still need to cable from the panel to the island. There is nothing for it, it’s big cement disc cutter time and lay some cables in.
This reminds me of a job I went to look at the other year, customer wanted downlights in a ground floor room, explained that I would do it by going upstairs, folding the carpet back, remove a couple of floor boards and wire them from above. No chance says the customer, new carpet just fitted bla bla bla. Ok I'll do it from below and you can get the ceiling patched up again after I've finished - "what, I don't want my ceiling damaging". So that was that, I made a swift exit.
So often this is the case, customer want loads of omelettes without breaking a single shell, I get it hanging doors. Me "Is the garage clear for planing/trimming the doors down?" Customer "It is clear but we would prefer it not to get dusty thanks" Me "Ok, if the weather is good, I will do them on the drive" Customer "Would prefer not as the dust is very difficult to get rid of"
What is your floor made off?? "I know its concrete" but is it solid or block & beam. If B&B there will be a void underneath.
The other week we were driving home from somewhere miles away and I was bursting for the toilet so we stopped at a garage or similar, went it, bought a drink and sandwich etc and said can I use your toilet please, we don't have one came the curt reply, a little riled I said "well where the **** do you go for a **** all day then." I just used the side wall of his garage instead, miserable ****.
A lady customer i did a job for i asked to use the toilet she said yeah fine, as i was peeing she brought me a drink walked into bathroom and put cup on the window sill i was to taken aback to say anything
Ok, lets think out of the box. Are their any pipes running to the island unit below the floor, could one be used as a conduit for a cable and it's original use forgotten use the hot water pipe as a conduit and gey the hot water on the island from an under sink heater. Or forget the gas hob, use electric and use the gas pipe as a conduit. Is their a cellar beneath the kitchen or is the floor a beam and block floor? If it's concrete on the soil surface then you might try a mechanical mole beneath the house. Would it be possible to drop the supply from the kitchen ceiling and disguise it as a feature? Without more data it is difficult to help more.