what you gonna try now ?
One option might be to call that Dave L chap and ask him to do the removal ... but teach u how to do , pay him well , it would be lesson woth paying for as youl come across these type of marks again and again .
Some brown/orange marks react well and quick with an acid ..or a reducer ...or an oxidiser ...but i have a feeling your furniture marks will be a hard to lighten as they come .
If it was me .... i would mix up a very strong oxidiser ...and a very strong reducer ... and try both to see if one is reacting more that the other
For the reducer ... i perfer the powder sources of sod met ( something like craftex shift ) ... because u can mix it super concentrate ...where as i wouldnt trust the liquid product versions , they might be ready to applt to a tea stain ... but u might need s small super strong mix to get any colour change on the furniture mark .
For an oxidiser ... i like hair bleach ..i get it in bulk , but nip down to boots and this kit should all u need to try it out ..
http://www.boots.com/bleach-total-bleach-kit-10239300or u could buy dye gone
If you mix up a sample of both the above i would dab each onto an area of one of the spots with a tiny paint brush or cotton bud ...
mix the sod met in very hot water first , apply external heat then if u like with an iron and towel or a steamer ...or a hair dryer , i perfer the hair dryer . Heat should also accelerate the oxydiser .
Even at that it might take time and several applications of whatevers working to get a dramatic colour change ( or it might not , wont know til u try )
It might even be a case of apply the oxdiser and leaving it overnight if thats an option to really get to whiteish colour ...
which brings u to your next issue .... unless your very lucky the new colour wont blend in at all with the carpet colour ... might be a very bright white stain .
in that case ... i mix some black wool dye really dilute ( almost transparent ) in a spray bottle , get a sheet of a4 , make a hole the size of the stain and put it over it .... them mist the dye over the stain , extract it ... then repeat up til the white mark ends up a light grey colour and blends more with the surrounding carpet .... chances are when viewed standing up u wont really notice the mark .