What is the likelihood of additional planning permission being granted
for timber holiday lodges (such as those sold by South Lakeland:
http://www.southlakeland-caravans.co.uk/SLLVlodge.htm) in and around
the UK's lake district? Is there appetite for or opposition to
additional lodge parks (e.g. from local residents, developers,
councillors)?

As far as I understand, these prefab lodges are mostly sold to a buyer for
cash up front (plus the annual maintenance fee) on a 30-50 year basis,
although there is the facility to sell them on midway through the
lease. You can also rent them by the week, although I am neither sure
how common this is nor particularly interested in it...

If you see any information about the resale value of these properties
then please throw that in, but that's definitely lower priority.