There are numerous bonds, so it's difficult to generalise. The best of them (and you won't know which that is until the end) will probably do better than a house, the worst certainly will not.
No-one can really predict over 10-15 years - you can look at what has happened over the same period in the past - but as financial advisors are wont to say (before giving advice on exactly that basis) past performance is not a guide to the future.
Not a lot of help I know - but a couple of thoughts:
after 10-15 years of letting the house is likely to need a lot doing to it before you would want to live in/sell it. Rental income is not assured - you may have bad tenants who won't pay or long periods without a tenant. You will need to look after it remotely or come home frequently.
but you are fairly assured it will have some significant value - with a bond it could go either way. Choose the right one your kids will be millionaires, choose the wrong one and they <could> get little or nothing.