I think you’re perhaps asking a bit too much. Its a nice frame (I have one but its the grey colour of the bike model down) but you can get brand new alu frames for ~£150 new. Add in a new headset and those Tektro calipers and you could be set up with all new stuff for just over £200ish as opposed to ‘2nd hand’ stuff without a warranty?
I also think Genesis stopped doing them for a reason and that was perhaps because they weren’t that popular?
Are Genesis so well known in road riding?
I think £100 – £150 would be a more realistic amount unfortunately. ebay probably the best bet.