HI,
As a registered student at a UK institution, you are entitled to supervision whether you are physically present or not. This may be via Skype or email, phone. ie whatever you can put in place with your supervisor. Discuss things with your supervisor now (although remember that August is both time for holiday and for attending conferences and sept is the very busy start of the new UK academic year, so not hearing from your supervisor at this time is not that surprising. Contact them again (maybe by phone to make sure you get hold of them)). If s/he won't play ball after that, you should refer the matter to your Head of Dept or School asap (so there is a record of your not receiving supervision from a set date) for them to put something suitable in place, which regulations require they do. Several people are indicating on this site that academics don't supervise for free. That's not entirely true! We regularly assist students who are not our own students because it is quite frequent that a supervisor won't have expertise in a particular aspect that becomes relevant for the student's PhD and that the said student contacts someone at another institution. The likelihood of your finding someone to help, however, strongly depends on the amount and the type of input required. If you do find someone who has the right expertise you need, you may have to compromise and offer in return to the individual helping you co-authorship of journal articles and research publications or such like. In all likelihood though, if there is a lot to do on your thesis, you are very unlikely to find someone to help you if you are not registered with that person's institution. It really all depends on how 'nearly done' you are and all you can do is identify someone and contact them to discuss the options. You may be surprised by what you get back. Your supervisor at your UK institution cannot withdraw supervision. So if you have not received supervision for a while and there is a record of that (hence informing your HoD) and if you continue not to receive supervision and cannot sort this out direct with your supervisor, your completion date may be pushed back accordingly if a valid case can be made. Remember though that you will have to be physically present for your viva at the very end, but the date would be set in consultation with you and usually months in advance. Yes, suspending/deferring is an option, but in my experience, those who do rarely return and complete. It all depends on how much your really want to complete your PhD. I would suggest you try and resolve this informally with your supervisor via a phone conversation and agree a plan of action now. Be clear about what you want/need from them. Everything else will be time consuming and once you go down the route of official complaints etc at your UK institution, a lot of red tape will be involved. Good luck!