Iv been recommended these two chairs..

[mrapoc]

Bearing in mind your budget have a look at the Activ 5

http://www.verd.co.uk/catalog/product_info.php/cPath/22/products_id/44

This should tick the right boxes, or  the Activ 6

http://www.verd.co.uk/catalog/product_info.php/cPath/22/products_id/37

In both instances you may want to add an inflatable lumbar support and then possible arms. We would certainly recommend Performance seat foam which is a memory foam and makes the chair more comfortable.

Im not sure on which outta the two to go for. I mean that performance foam is a must get, the video recommends that users over 5ft 10 goes for a seat slider (im 5ft 11 and only 16 so still growing). I dont care for chrome feet (18 stone and over - im thankfully under 11 ) but the arms would be good for computer use (at a guess, never used them)

Which do you reckon is the most justified buy at stock configuration? Ill end up adding stuff like performance foam to it anyway

[Glenn]

I like the Activ 5, but with the head & arm rests. Are you able to try them anywhere, to see which model suits you better?

[mrapoc]

well the the activ 5 has a bigger back which is key to me i reckon.

think the more important upgrades to me would be the memory foam and arm rests

the lumbar support can come from a towel or something and the headrest can always be purchased later im assuming 

[Sebby]

I know nothing about chairs. Perhaps it's worth emailing them for some advice?

[Simon]

Sit at the PC for long enough, and you'll soon be 18 stone and over, Sam. 

[Gary]

I have a test chair coming from Albion chairs, its called a spynamic SD1, covered in memory foam etc its expensive but for me I have little choice as I can hardly walk now I am on 75mg Morphine a day as a maintenance dose with 10mg of liquid morphine for breakthough pain plus Gaberpentin.
They do a range of chairs though at different prices.http://www.albionchairs.com/
http://www.cdfltd.co.uk/sec_orthopedic/sec_orthopedic_seating/spynamics/spynamics_sd2.htm this is the chair I'll be trying they come in pretty much any colour you want and you can have a headrest as well.