Currently, I'm studying GCSE's but a few months ago I decided I want to take a gap year. My best friend also wants to join me so this is great. However, I have some worries:
Do all universities offer a deferred enterance?
We are thinking of travelling Europe for a few months, particularly France, Italy and Eastern Europe, then heading to South East Asia for the rest of the year, roughly how much will this cost?
I don't think you'll have any problems with deferred entry. The biggest consideration should be your budget. If you decide to do Europe then South-East Asia then it will add up to a fair amount. How long do you plan on traveling? And what would you like to spend at most?
If you are concerned about budget then you may want to consider skipping Europe and heading right to South-East Asia. I'm heading to Kuala Lumpur next month and a direct flight return ticket was £550, which is what I suspect what it would cost on average to return from most South-East Asian countries. Flying within the region is fairly cheap, especially in non-touristy seasons
e.g. in October:
Kuala Lumpur -> Bangkok is £20
Bangkok -> Siem Reap is £35
Flying to Japan is a little more expensive, but still reasonable (£125 return Bangkok -> Tokyo -> Bangkok). If you want to travel a fair amount, it would be reasonable to assume flights alone will cost no more than £1000 total, including your return to the UK.
Accommodation is the trickiest part to estimate as it depends on how long you want to stay, and also what standard of accommodation you want. Hostels in the region are incredibly cheap, but if like me you prefer private accommodation on a budget, then the prices are still reasonable, especially if you are traveling with a friend. It's been a couple of years but here are a rough estimate per night what I think I spent.
Thailand: £25 Bangkok, £15 Chiang Mai
Cambodia: £15 each (2 people)
SIngapore: £35 each (3 people)
Malaysia: Not too sure as was studying there, but price probably between Singapore and Thailand
So it really does depend on your desired length of stay/quality of accommodation.
If you don't mind shared hostels then the price is much cheaper than this. Sorry if all this information is a bit muddled but I hope it can help a little. I can't offer too much advice for Europe as I haven't traveled there too much.