You don’t really need the sump plugs just reuse yours, washers yes. Oxygen sensor plug and washers??
Halfords for the oil, I used my discount card last time although they have 10% off with the code if you spend over £30.
Not sure I you can get the £10% then the club discount too which is -8%, worth a try.
Edit…10% off online purchases, not in store. Definitely use your club discount card in store for discount.
I only do a few thousand miles per year, my car lives in the garage all year. I change the oil and filter every two years, the oil comes out almost looking like new.
My daughter’s old car, never had the oil and filter changed in maybe 5 years, she just kept topping it up, and only when the oil warning light came on.
Considering your car has only done about 3000 miles on the current oil, in my opinion, it ought to be OK for a few more thousand.
Although for your own piece of mind, it wouldn’t hurt to change oil and both filters.
I find GSF car parts very competitive on price.
I try to remember to write mileage and dates on receipts when the work has taken place. Not all of course (parts) come with a receipt. It’s all kept in a folder with MOT sheets V5 etc. If I buy parts like a chrome fuel lid worth £500 now (joke) I save the receipt, it all goes to show how much money has been wasted/lavished on the car.
My current car came with all manner of receipts like underseal ones, tuning mod, smart top, etc besides service ones, it’s why I bought it straight off.
I use a service log spreadsheet which I print off and tick the items done. This gets put into a ring binder, together with receipts.
If you refer to the “Service Check Sheets” in the Downloads section, the one for a NC might be a good basis for possible modification.
I save the receipts and circle the invoice number and add it to the service book under that service to cross reference.
With the mazda because I did such a bulk load of servicing all at once (most items being long interval jobs) I used my label maker to put the services inside the fuse box lid for my own reference.