These web pages hopefully provide some information that may help your stay at the flat.
Utility cut-offs
Gas - the main cut-off valve is on the gas pipe by the gas meter, in the cupboard by the kitchen window.
Electricity - the main switch is on the consumer unit, in the cupboard by the kitchen window.
Water - the riser stop cock is at the back of the cupboard under the oven. NB there is no water meter.
Replacements: bulbs, batteries, hoover bags
Spare bulbs in the kitchen drawers. All replacements should be LED, filament type when possible as they are more efficient. For normal bayonet clip (BC aka B22) bulbs, I generally recommend 'candle' or 'mini globes' as they are easiest to put in and remove:
Bedroom main lights are all B22, minimum 800 lumen (60W equivalent), eg Sainsbury's, £5 for 2.
Entrance, WC and landing - all B22, 470 lumen (40W equivalent), 2700k/warm white, eg Sainsbury's, £5 for 2..
Lounge uplighters - all B22, dimmable, 470lm, 2700K/warm white, eg Sainsbury's Home LED Filament Standard 60W BC Dimmable, £6 for 2. NB they must be dimmable otherwise a) they don't dim well, and b) after a while the dimmer circuit burns out (expensive to fix...)!
Desk lamps should evenly illuminate your working area, so avoid spotlight bulbs; have low power 250lm (~ 25W equivalent) bulbs. NB get 'cool white' (6500K) for work lights as it's said to be better for concentration, and also when combined with the warm white main room lights colour rendering can be improved. eg:
for the GU10 desk lamp: Eveready 3W wide beam (110°) - NB the more common 38° spotlight bulbs are not suitable for desk lights. NB2 bulb sucker in the bottow kitchen drawer.
Bathroom spotlights - 5W, MR11 GU4, wide beam (> 90°), natural white. Eg these on eBay £12 for four.
Kitchen pendants - dimmable MR11 GU4 base LED 4.5W 36 deg beam; these are the most difficult to find - I have a couple left, best to contact me to replace them.
The carbon monoxide alarms take two AA batteries. The smoke alarms are mains-powered, with battery backup whichrarely needs to be changed. TV remote takes two AAA batteries.
Get vacuum cleaner bags for the 'James' either from myhenry.com, £4.50 for 3 or £10 for 10 free delivery, or walk down to Argos (on Old Street, 7 min walk) and get 10 for £10 over the counter.
Detectors
Checking the smoke and carbon monoxide alarms is easy and definitely worth-while!
smoke/heat detectors - although these have batteries as a backup, they are mains-powered normally so their batteries rarely need replacing. Each has a 'test' push button, and as they are interconnected, they should all beep when just one button is pushed.
carbon monoxide alarm - these start to beep and show 'lb' when the battery is low.
Cleaning materials
Spare cleaning gear might be found under the kitchen sink:
dishwasher - all-in-one tablets are easiest (combining salt and rinse-aid).
wooden floor - generally just wipe with a damp cloth, but can be polished with mansion wax.