She is a false widow, Steatoda nobilis. She doesn't look fully grown, her markings are very defined and legs still a little stripey.
If she bothers you, she can be relocated to somewhere outside. They like window frames, porches, sheds & conservatories. If she finds a nice hiding place (hole/crack in brickwork, or timber, etc.), up high, she'll most likely spin a web and stay there.
Keep an eye out, but don't fret. Babies, tiny ones, aren't likely to be able to break skin, spiders much younger than yours spend most of their time hiding in cracks & crevices, especially when there is activity nearby. They seem to disperse when very small & don't hang around in a colony, female adults are very territorial & intolerant of neighbours. As the weather cools & prey reduces they will become less active.
Males only typically live a season/year, stop eating when mature & die off as the winter comes.
I am so sorry to keep asking questions. I just wanted some advice about the following re the spider above. About four weeks ago I was loading my washing machine when I felt what was like a wasp sting...no other pain after that...no swelling etc .....but within a few minutes I was rushed into hospital and stayed for a week with a suspected heart attack. I was treated for this with meds, angiogram and am waiting for an mri. All clear at the moment. Then of course, a few days ago I find this spider in my kitchen, on the windowsill, near where my washing had been that day. Is it possible I was bitten by her through my washing? Would there not have been symptoms on my skin......What do you think......Many many thanks for all your help. Also, I have been told that horsechesnut spray and chestnuts in every room will keep them at bay. Is this true?
You have been so very helpful.
I'm very sorry to hear of your experience, it sounds terrifying.
Unfortunately, I have no medical experience of S nobilis bites, nor experience of a bite from S nobilis myself (I have been bitten, twice in 45yrs, by other spiders, resulting in localised swelling, redness, itchyness & aching…much akin to a wasp sting, one bite left a very visible pimple).
It doesn't appear to be possible to definitely rule out the spider as the culprit, nor to confirm it. I have heard about using horse chestnut to deter spiders, but have never tried it myself...you have nothing to lose by giving it a go?
So bearing the above in mind & for what it is worth, here are some things to consider regarding S nobilis:
Bite reports often state the bite was not initially felt.
The spider has to break the skin to administer the venom, suspected S nobilis bites (& confirmed S grossa bites) usually result in a visible mark/weal.
Any suspected bite is difficult to confirm if the culprit isn't seen, or captured/identified at the time.
With many suspected bites, initial symptoms are a mystery/assumed to be a spider, then some time later a spider is seen in the general vicinity & automatically becomes the suspect.
In bites that are most likely confirmed (the spider, or its body, are found in bedding/clothing at the time of/shortly after the bite) localised pain, swelling & visible evidence are typical. So I tend to agree with your thinking that there would be symptoms on your skin.
Steatoda nobilis can bite, but their general behaviour makes this an extremely rare occurrence, even in areas where they are well established (they are simply everywhere, where I live). Your symptoms do not seem to fit the typical description of other bite reports.
All that said, if the spider's presence bothers you at all, you will feel better if they are removed. I use a plastic drinks bottle, screw the lid on & cut off the base of the bottle as squarely as you can. The flexible material makes it very easy to scoop up the spiders on flat surfaces. Some are better than others at climbing back out but a shake or tap of the bottle can drop them back to the bottom/lid end.