If you go piggyback (which I might end up doing) then go Dastek. Although E-manage has been recommended too but I've not done any ground work on that. That's not technically being able to 'do denso' as it's a work around. It's possible they say they will solder on a ROM chip to be able to access the ECU but I've heard horror stories about ECUs failing soon after and them having to fork out £500-600 on a new replacement ECU. That may well depend on who's doing the work though of course. But you can never be 100% sure of who you're dealing with.
Sounds likely mate, give them a shout