I am not an accountant...
I do own my own LTD company. In earlier times I would suggest that it depends on circumstances - there are ways to (mis)use LTD status for tax purposes even on £30k earnings.
However on £30k the tax benefits are small and the accountancy charges will probably easily outweigh them. More than this, if the duration of the contract is short then closing down the company is (according to others I know who went from LTD to perm inside their end employer) a massive arse to do so. You have to close it down too as otherwise you are still responsible for all sorts of filing to HMRC on a very regular basis.
IR35 changes will almost certainly be reintroduced next April and this years aborted run showed that many employers were not keen on using LTD personal companies at all under the new rules.. even for contractors that had been working for them for years & years. So at best, your friend will likely have 9 months or marginal gains for long term pains and additional costs.