As a half breed Englishman I am not sure you will want to take guidance from me, but remember you have to pay to come this side of the bridge so there’s something to be said for being born on the English side.

You’ve picked a time and a half to start running, coming up to one of the wettest, windiest times of year. When it’s cold and wet outside motivation to start is hard but it will feel worth it at the end of the run. Not sure which part of Cornwall you live in but I know most of it needs a bit of ironing and running on hills can be hard for begginners, so choose a route you are comfortable with first and foremost, keeping in mind likelihood of green areas getting boggy etc. Holding a rugby ball seems to help people run in Cornwall, may be worth a go.
Seriously though as a fan of outdoor running I know you are going to find this difficult and demoralising at first. You are carrying more weight meaning your pace will be a lot slower. You will likely not really get warm due to the intensity you will have to stay at and the time of year. This may not seem motivational but it has to be considered, because if you expect it to be wonderful from the off you will hate it and stop.
The only way you will start running is to plan it and do it.
Find a simple route that will be very easy, be realistic
Get hold of a GPS app for your phone, assuming you have a smartphone like most of the modern world, to have you monitoring what you have done
Set alarms for the time you need to be getting ready and starting your runs and do it regardless of how you feel or what the weather is doing
Give yourself at least one rest day between runs at first
Be proud of yourself when you have done your full weeks planned running, it’s an achievement, don’t forget it

As someone who is 1.5 times my genetic weight I know how much impact weight has on running pace. My extra weight has been built but when runing this is irrelevant, I’m still heavy. You will need to remember this too and accept speed will increase as you get used to running then more as you get lighter.

Trimming down will take time. If you have read any of my stuff on here you will know I am not a quick fix fan, because they don’t help people using them and aren’t designed to.
The key will be setting long term realistic targets and working toward them with gradual changes. 1 pound of fat is 3,500 calories so if someone says they lost 5 pounds of fat in 1 week and the difference between their intake and activity doesn’t look like 17,500 calories (2,500 a day) they are kidding themselves and may have lost some fat and a heap of water.
I tend to ask people not to use scales to monitor progress because weight can be fat, water or muscle, so increased fitness can mean lean mass gain and fat loss make for stable weight or even weight gain which dieters find demoralising.
Clothing fit is a good guide as is the mirror if you can use it well. If you insist on using scales the aim should be 1 or 2 pounds a week loss at most, remember this will mean a consistant 500 or 1,000 calorie a day deficit.

One basic warning regarding that size 8 fit. I was incredibly skinny as a youngster but the strain I have put on my body through training and additional bodyweight have forced my body to adapt at a skeletal level. Carrying more weight needs heavier set bones and where possible broader structure. This means you could literally have a larger bone structure than you had at size 8 and may never fully get that back healthily. This doesn’t mean ultimate failure but is something to remember, you may end up a fit trim size 10 rather than an 8 at the end of this purely due to adaptations your body has been forced to make, this is still success.
I was 9 stones, and am now around 13.5. Getting to 9 again now would mean carrying even less muscle and fat than before because my frame will be bigger and heavier by a proportionately small but still significant amount.

Weight loss for those of us who like our food is achieved the same way as for anyone else, by either decreasing intake (painful), increasing activity or a bit of both (preferred).
Being active and self-employed likely means you have little time to plan meals and eat some quite random junk as and when you have time. In order to eat less and still enjoy it you need to think ahead and organise. Aim to cut intake by 10% across the board, so you will be still eating what you enjoy just slightly less of it. The cut will be felt but your body will adapt to it fast. If you plan ahead and eat regularly this will feel easier by enabling you to still enjoy your food and have food in your system a lot of the time.
Adding in the running should easily cover 10% or so increase in activity so go for it.

Give it a go and keep us informed. Alternatively come back saying what you have tried and where it went wrong if it doesn’t work. There are always alternatives.