Petition Mansion tax £2m threshold is discriminatory

To consider a mansion tax threshold on homes valued at £2m is particularly unfair on those who have homes in the £2-2.5m bracket.
The Government has only just introduced an increase in stamp duty to 7% for homes valued at more than £2m. This has already affected the values of homes marginally over 2m.
By adding another tax with the same threshold will mean those who have homes currently valued in £2-2.5m bracket will find it extremely difficult to sell without discounting to below £2m.
Not only will this create large capital losses for an albeit small number of people affected it will also severely distort the property market in general.
I do not agree with any form of mansion tax but at least consider making the threshold less discriminatory to this band of homeowners.