Re: £700 for a decent chair
Not far off.
You can get 'an office chair' for £75. If you're under the age of 40 and/or intend to make other people sit on it then it might suffice. For six months to a year at least.
You can get 'an office chair' for £150. If you're under the age of 40 and/or intend to make other people sit on it then it might suffice. Could last a couple of years.
*But* if you're 40 or over and intend to sit in the seat yourself then anything less than £400 is a poor choice. £700 quid for a chair that someone of advancing age has to sit on for eight hours, five days a week is a worthwhile investment. In my opinion no-one over the age of 40 should be required to sit in a chair that can't be independently adjusted for height,pan depth/tilt,back tilt,lumbar and arm rests. You don't get chairs that offer all that without spending some serious money.
I would also suggest that anyone over the age of 40 should be offered a free ergonomic assessment every couple of years. A really far-seeing employer would do that at 30 and consider upgrading the seat if appropriate. Sitting is not 'restful'. It's surprisingly stressful on the human body and 'any old chair' is injurious to your health.
P.S.:I'm not an ergonomics expert nor office furniture salesman. I'm just a 45 year-old whose body won't tolerate sub-standard seating any longer without aching.