Firstly, note that there are only 8 or 10 cases so far where IR35 has been bitterly fought by the Revenue to make a ruling against the favour of Director/Shareholder especially with section 660A(This is is applicable if you use your partner/wife/shareholder to channel non-NIC paid dividend income to your personal/family benefit).
In my view, if you are starting contracting you really do not need IR35 Tax liability insurance - which PCG does not cover anyway (unless of course you charge a humongous rate of over £2000 per day and plan to shift income between 4 partners who are shareholders of your company

to avoid NIC all together )
What you need cover for is basically "professional representation costs". This is a basic need as an when Revenue initiates an investigation process (note: this could even be non-IR35 related tax inquiry). Here a tax lawyer and his/her legal back office will support your accountant with your case files for the the duration of case. Please note, with "professional representation cover", tax liability is not covered (if Revenue comes to conclusion that your working practices was really inside IR35 while you declared yourself outside)
Hence personally, I would
not recommend both solely for IR35 tax protection purposes.
I was a PCG member till 2011, and I have not renewed with them since then. Reason being, I realised I wasted a lot of money on something for years when my accountant started offering the same cover at a fraction (to be precise: 1/5th of the PCG premium membership cost).
This is my advise:
Since you are starting contracting using Ltd company, I am assuming you must have already found an accountant.
Ask your accountant whether his monthly/annual service fee covers "Revenue (HMRC) investigation fee protection costs".
Most accountants 'absorbs' these investigation fee protection cover costs and offer it to their clients since it saves a lot of hassles to them as well..
Hope this helps.