As you have discovered, ACCA are strict about the issue of practising certificates and do require a certain number of years of relevant practice experience supervised and signed off by a suitable manager/principal. The ACCA don't have any different levels of "practice", so the practising certificate allows you to do everything from a self employed window cleaner to a multi million pound business with dozens of staff. As third parties, such as banks, landlords, HMRC, potential buyers, place reliance on accounts signed off by an ACCA member, then ACCA are right to put safeguards in place to ensure their practising members are competent and experienced.
It seems that your experience has been in industry, hence why you can't get your practice experience record signed off - you simply don't have enough practice experience. I moved from practice to industry after 15 years experience and as a manager in an accountancy practice - I moved back to practice after just 2 years in industry and had to effectively take a backward step on the ladder, back to accounts and tax preparation for a year or two to get myself back to speed as so much had changed in just two years in the world of self assessment, VAT, CIS, accounting standards, etc.
Moving from industry to practice is never easy as they're competeley different skill sets. Practice is more about tax, and not just income tax, it's also VAT, CIS, NIC, CGT, etc that even the smallest businesses have to consider and deal with. The small amount you'll have learned in these areas doing the ACCA exams is just an overview and won't cover the day to day queries you have to deal with in practice.
Ideally, you need to get yourself a job in a practice, but that will be hard as you lack relevant practical experience and want to work part time. But it's the right way to do it, as you can then do a few years, get your experience signed off and then start up your own practice once you have your practising certificate. You just need to persevere as it won't be easy - perhaps get yourself on the books of a couple of accountancy recruitment firms as they're usually good for "unusual" people, i.e. they may know better how to fit an industry accountant into a practice role.
If you can't get a job, and want to start your own practice, then you will either have to restrict yourself to what ACCA will allow you to do without a practising certificate or leave the ACCA.
Without a PC, ACCA allows you to do book-keeping, management accounting, VAT returns, payroll, etc. You're just not allowed to prepare nor submit final accounts nor tax returns, nor sign off reference requests for mortgages, landlords, etc. Given your industry experience, you may be able to establish a good practice just doing management accounts, forecasting, book-keeping, setting up accounting systems, etc as more of a consultant to businesses rather than their official "accountant". Plenty of firms need someone to "do their books" and book-keepers are always busy these days - if you can go one step further than book-keeping into management accounting, forecasting, and maybe helping set up costing/stock systems, you could well find yourself busy without the year end accounts/tax return work. You'd also start to build relationships with your client's external accountants who do their year end accounts/returns and maybe start working together or get someone to sign off your experience record after a few years of working together?
The alternative of leaving the ACCA is a difficult decision, but at the end of the day, you passed the exams and got the certificate, and no-one can take that away from you. You can't "market" the ACCA qualification in practice with a PC, in fact you can't mention it at all, but it's still there on your CV if you want to go job hunting in years to come and is still relevant - many industry ACCAs give up their membership but still manage to move from job to job on the back of the qualification and experience, so all isn't lost! Once you've left the ACCA, you are free to practice (as is everyone!), as it's the ACCA who are restricting your practising. You could join AAT instead (I think you'd be exempt from their exams by virtue of passing ACCA), and they have a more relaxed attitude to practising authority where (I think) you can get different levels of authority to practice depending upon your experience. Or you could join another body such as ICPA who rely more on experience than qualifications, or "practice" without any professional body at all - although banks/landlords etc won't accept your references etc for your clients and prospective buyers of their businesses won't be happy with accounts signed off by someone with no qualification (remember you can't say you used to be ACCA!).