Hate you Tiger_Moth?, no way, I just want you to be sensible, your last post here was just that, great!.
OK I realise you only want a PPL, however you will have to have FAR more lessons in a Tiger_Moth than you would in a more sensible trainer (I would reckon at least 10 hrs more)therefore IT MAKES SENSE, to train in a proper trainer just for the cash savings BY FAR.
When you 'land away' in your Nav Qual to be 'signed off' at two 'real' airports have you any idea how difficult it will be to even taxi the Tiger Moth on tarmac let alone land/take off on it, I also have doubts that major airports (where you have to landaway for PPL) would even accept a student solo in Tiger Moth, even if they sent out a 'follow me' truck you would struggle to even see it whilst in front of you let alone follow it!.
At my local club we have a Cessna 140 (1940's)taildragger, solo it costs about £52 per hr with an additional £24 for an instructor, therefore for £76 per hr you could do your PPL in a taildragger anyhow for about £3600!.
You have failed to discuss the problems with cockpit management in an open cockpit, only for the VERY experienced.
Also who on earth are you going to find to swing the prop and remove the chocks at the likes of East Midlands/Newcastle/Humberside/ airports etc whilst on Nav Qual's?.
It's a case of 'get real' or fail or just become a student for ever!.