Delete it yourself from your profile. Some records are kept by law.
You → Delete account removes your profile, your listings, your saved items and your read receipts straight away.
Some things stay: messages remain visible to the people you exchanged them with, reports you were involved in are kept, and records of protected sales are kept for six years because HMRC and consumer law require it.
For a copy of your data, or anything else about it, email legal@reloot.co.uk from the address on your account. We answer within one month.